Labour Laws are basically The Last Autumn's version of Purpose Laws: they're your second Law tree, just like in A New Home you don't have access to them at all until a plot event unlocks access, and eventually you will pick one of two Terrible Paths to commit to, where following your choice to its ultimate conclusion is always a dystopian nightmare.
Unlike Purpose Laws, the unlocking occurs in two stages. When you first get started on Generator construction, Work Safety is not a mechanic: a bit after you've first started actually working with a Generator tab building, you will be informed of an accident almost occurring, Workplace Safety will kick in as a mechanic, the following 9 Laws will be unlocked, and you will be given a quest to pass either Short Shifts or Safety Procedures so as to mimprove safety.
Then once the Shaft Structure (Your very first step in assembling the Generator) reaches 70% progress, an Accident willl unavoidably occur. At that point you'll get the prompt to side with the Workers or side with the Engineers, determining what the rest of your Labour tree will be; those Laws don't actually 'connect' to any of these core 9 Laws. though. You effectively have 3 Law sets, just with the second and third shoved into the same 'tab' by the game. It's kind of weird and I'm not sure why they didn't make it truly three tabs. Was the code just not suited to adding a third Law tab to the Book of Laws, at least not without it looking terrible?
In any event, also different is the visualization aspect. Where Purpose Laws have Faith go up and Order ho down, the Labour choices both go up. You're always climbing a tower to reach a summit of awful. Sure, okay.
Anyway, let's cover these core Labour Laws:

Short Shift
Requires: Nothing.
Law Cooldown: 18 hours.
Unlocks Short Shift at all Generator tab buildings. A Short Shift lasts from 8:00 to 16:00 instead of 8:00 to 18:00, and raises Workplace Safety by 1 while active. Passing this Law also immediately raises Motivation a little.
Basically, you can sacrifice 20% of the workday to push up Workplace Safety. This is absolutely worth doing when Workplace Safety is at -3 or worse, because Accidents become possible, and these can do things like produce multiple instant Amputees or make many laborers on the job Ill and/or Gravely Ill all at once. (I'm talkinng like a 50-Worker site ending up with 20 people all seriously screwed up, unavailable for at least the rest of the workday)
Unfortunately, Short Shift is a victim of Frostpunk's ongoing reality that it is not a turn-based game even though it comports itself in various ways as if it believes itself to be one. You can toggle shift length at will, and so can get the Workplace Safety benefit for 8 hours and then still work those last two hours anyway. The game has an event that will chide you for doing this, apparently, but not a real limit on doing so; Short Shift really should've been something you can't cancel out of once commited to it, especially thanks to...

Work Standardization
Requires: Short Shift.
Law Cooldown: 18 hours.
From now on, Short Shift applies 10% more Efficiency while active, but also raises Discontent a little. Passing this Law also immediately raises Discontent.
Oh boy.
Yeah, you can just get 8.8 hours of labor out of people by claiming they're on a Short Shift, and then get the other 2 hours anyway by swapping to regular hours at the last second. That's... that's just great Frostpunk, thanks for this horrible design.
I personally don't do this because it's not necessary and I hate what an obvious, dumb exploit it is, but yeah.
Anyway, as I implied a moment ago, non-exploitive use of this effectively means a Short Shift only actually gives up 1.2 hours of progress by default while still improving Workplace Safety, making it an even more appealing choice. The Discontent penalty exists, but isn't really a strong reason to ignore Work Standardization: you really ought to pass it in every run in practice, even if you're playing 'honestly'.
Next Law!

Extended Shift
Requires: Nothing. Incompatible with Two Shifts.
Law Cooldown: 18 hours.
Allows all worksites to switch their working hours from the usual 8:00-18:00 length to instead 6:00-20:00, a 40% increase. Doing so raises Discontent slightly, and passing this Law immediately raises Discontent slightly.
It's our old friend Extended Shifts, but now it sucks because instead of being gated behind Emergency Shift, it competes with what amounts to a superior version of Emergency Shift:

Two Shifts
Requires: Nothing. Incompatible with Extended Shift.
Law Cooldown: 18 hours.
Allows all worksites to switch their working hours from the usual 8:00-18:00 length to instead 24 hours, but also doubling the needed labor force to operate them and splitting the assigned labor into two 12-hour shifts each the size of the normal labor limit. Doing so also raises Discontent slightly, and passing this Law immediately raises Discontent slightly.
Hi Emergency Shift, I see the devs tried to rework your overpowered self and somehow made you even more stupidly abusable.
I get the thought process here, and if Frostpunk was a turn-based game (Or faked it more adequaly), this would actually be a pretty good pair of Laws that would be an interesting choice: get 40% more labor on a worksite at the cost of Discontent, or get 140% more labor at the cost of both Discontent and doubling the amount of labor you have to apply. That'd be cool!
In actuality, this is largely Better Emergency Shifts because...
-You don't spend Food or suffer deaths from using it. It's just free.
-It doesn't have a cooldown, and so can be abused continuously wherever you need it, instead of only every other day.
-Most cringe-y of all, Frostpunk is a real-time game and you can freely change shifts at will: as such, you can run Two Shifts through the night, then turn it off on a worksite and redistribute labor during the 8:00-18:00 period to other worksites, then switch back to running Two Shifts wherever you need it at 8:00.
This last point can in fact let you get 8.8 hours of labor with Short Shift and immediately proceed to switch to Two Shifts to thus get 24.8 hours of labor out of a day at essentially no meaningful cost. Shift length really needed to be something that the player couln't mess with a will at any worksite...
I personally don't abuse these particularly inane exploits, partly because seriously they're such gross exploits but also because that's a tedious daily hassle that's really not necessary, but even just playing 'honestly' still leaves Two Shifts as grotesquely powerful. Most glaring is that it's the ultimate form of Workshop Shenanigans: instead of running two Workshops to alternate Emergency Shifts on, you just run one Workshop with Two Shifts to tear through techs at 240% speed at even less cost than Emergency Shift abuse imposes in other scenarios.
It's less egregious with other worksites, but it's still ridiculous. If you have two Fishing Harbors, shunting one group of Workers to the other is the same labor but 20% more Raw Food per day at basically no cost. Same with eg Sawmills, Gathering Posts, etc...
... only it's even better than that suggests because The Last Autumn centers itself so heavily on chokepointing labor considerations. The Generator construction is particularly egregious, as it's done in stages where you can be blocked from starting on the next stage by a single worksite; finishing the Shaft Structure is not something you can speed up by building a second Shaft Structure. Similarly, there are only four slots in total for Docks and Fishing Harbors, and so extracting more work out of a single building is an advantage you simply can't replicate with more parallel worksites once all four of those slots have been eaten. More debatably, the buildings for constructing the Generator construction resources can technically all be massed, but two of them require Steam Cores and they all compete for the limited space in the Generator Build Zone, so there are sharp limits on your ability to actually do this; in practice you're probably only going to build one of each, and so squeezing more work out of a single building once again gains extra value.
The whole thing is predictably very, very powerful.
Oh, and I'm pretty heavily implying it with all the prior statements, but I should explicitly state that Two Shifts is very much the preferred choice out of these two Laws. That said, I should mention that if you go with Extended Shift instead, using it heavily will eventually prompt the usual 'can you stop using it everywhere all the time?' complaining event, but blowing it off in The Last Autumn has slightly different consequences from in other scenarios: instead of just increasing Discontent a very ignorable amount, it actually adds +1 Strike Risk to any location you're using Extended Shift at, lasting 2 days. Which... doesn't have much teeth to it, as Extended Shift is already more of a tradeoff on Generator tab buildings; the places you will most freely abuse it at are all the other worksites like your Workshop(s) and your Fishing Harbours and your Sawmills, and of course they're not susceptible to Strikes. (This is one of many, many examples of how janky it is to me that Strike Risk is exclusive to Generator tab buildings)
I should also explicitly point out that since Motivation changes at 6:00 in the morning, it aligns perfectly with Extended Shifts, unlike the weirdness in other scenarios where Extended Shifts results in an hour of work occurring before a day's temperature change will occur.
From a more narrative representation sort of perspective, I far prefer Two Shifts to Emergency Shifts, and I'm actually pretty frustrated the game presents Two Shifts so negatively. Getting more labor from a worksite by having multiple shifts working around the clock isn't fundamentally a dangerous, exploitive, abusive practice (unlike the Energency Shifts situation of 'you lot are just not sleeping for 36 hours'), and anyway Frostpunk itself shows no recognition of any of the real problems with implementing such: your employees don't complain about having trouble sleeping because there's always heavy machinery operating all hours within shouting distance of their tents (Which logically would have basically no sound dampening), the game doesn't have the night shift more likely to suffer accidents due to inadequate lighting, you don't have to specifically have a kitchen night shift in support of the other night shifts...
... I'd rather have Two Shifts be the basis of 'get more work out of this jobsite' in other scenarios rather than Emergency Shift (I'm looking at you, Frostpunk 1886), and also prefer for the game to not treat it as negatively as it does. (And/or for it to try to incorporate some of the realistic problems with making night shifts work smoothly) All this on the assumption of also fixing the 'this game thinks it's a turn-based game, but it's not' problems, of course; it's ridiculously abusable as-is. (I'm a bit baffled the devs didn't reuse the 'hunter resting from the hunt' logic for night shift employees, frankly)
Anyway, these each have a Law locked behind them, so let's get to those:

Extended Shift Compensations
Requires: Extended Shift.
Law Cooldown: 18 hours.
Employees on Extended Shift eat an additional half a ration per day, but Extended Shift causes less Discontent.
Oh boy.
First of all, the idea here is really bad: food in The Last Autumn is tight enough you shouldn't be cavalier about spending it, whereas Discontent still doesn't really have teeth. This also does nothing to compensate for how Two Shifts is simply massively better than Extended Shift: reducing the Discontent from Extended Shift doesn't give it anything meaningful over Two Shifts. The idea here simply doesn't make sense.
But it's worse than that: as my strikethrough suggests, the food part doesn't actually work! Which honestly isn't surprising given that Child Labor also also has a 'extra food for citizens matching specific working conditions' effect that doesn't work at all. I frankly have no idea what the devs imagined the mechanics even could be here given how they've set up the game: once again, if Frostpunk actually were a turn-based game, or remained real-time but actually had shifts locked in per day, or something of that sort, it would be straightforward enough to just eat a Ration for every 2 employees on an Extended Shift at the point everything was confirmed, but with Frostpunk's actual setup... yeah, I'm not sure how you'd even make this work on a coding level.
That it's broken is sort of fortunate in practice since it very, very slightly improves Extended Shift's case by making its follow-up Law a complete freebie improvement, but it's really not enough. And Two Shifts gets its own follow-up Law:

Shift Work Coordination
Requires: Two Shifts
Law Cooldown: 18 hours
Activating Two Shifts now raises the maximum employees needed to only 50% more than a single shift (Rounding down) rather than 100% more, but Two Shifts raises Discontent more. Additionally, passing this Law noticeably raise Discontent immediately. Each shift is still equally-sized, and so will be roughly 75% of the employees needed for normal operation
The game frames it as Two Shifts requiring 25% less citizens, which is true of the total but is easy to misread as a smaller impact than its true impact. Regardless, this can be viewed in to basic ways: the first is that it massively improves the labor distribution efficiency of Two Shifts. eg instead of cramming two Sawmills of employees into one all-day Sawmill, you can cram three Sawmills of employees into two Sawmills that are running all day. Alternatively, you can view it as a significant improvement to work speed on Generator construction: one of the main limitations of Two Shifts is that doubling the employee requirement is insanely demanding when it comes to Generator components, as many of them have a base max of 50 Workers, and the ones that don't still have a very high max of 30 Workers. Pulling 50 Workers onto the current Generator stage is already often requiring you pull basically all your non-essential labor for a decent chunk of the run, in which case pulling 100 is probably outright impossible; knocking it down to 75 might still be too much to fully fill, but getting to eg 60 Workers assigned will jump from 'the night shift is working at 60% Efficiency' to 'the night shift is working at roughly 80% Efficiency', meaning it's working 33% faster in real terms.
That said, I personally find Shift Work Coordination a dubious deal. By far the biggest benefit to Two Shifts is how much it turbocharges your research, and shaving off a handful of Engineers is basically no benefit for that, while the Discontent increase must be shouldered continuously anyway. This is the most egregious point by far, but there's a similar point regarding Fishing Harbors and even Reloading Stations to a degree: Shift Work Coordination is primarily advantageous if you are using Two Shifts heavily wih the Generator construction process in specific, where the worker count per worksite is high. Among other points, Two Shifts' Discontent penalty is scaled to number of worksites, not number of people working; having 5 sites drop from needing 20 people to needing 15 is the same number of people freed up as having the Core drop from 100 people to 75 people, but the former is 5 times the discontent penalty as the latter.
I'm similarly unfond of it from a narrative standpoint. Its core concept is that micromanaging laborers somehow results in needing fewer people to get the same amount of work done, applying only to Two Shifts in specific. This is pretty nonsensical on the face of it just for that last point, but is also part of a weird, frustrating trend with The Last Autumn; as we'll be seeing more with the Engineer Laws, this scenario seems to believe that leadership constantly micromanaging minions can produce superior results, with the only tradeoff being that the people being micromanaged will resent it. That's tempting to believe if you play a lot of games where the player can perfectly micromanage every single minion to optimize their results, which Frostpunk is broadly part of that collage of games, but that's pretty unrealistic to achieve in reality, and even if you can achieve it... well, plenty of people applying such a micromanagement-centric approach to real life have had it go quite wrong, and not necessarily by virtue of a revolt occurring or the like. Fundamentally, management from above is limited by its distance, the lesser quantity and fidelity of information compared to the people who are right there, not to mention the delays involved in relaying information up to management and then relaying orders back down from them. Unless you genuinely are surrounded only by people who are basically actively committed to making bad decisions, intense micromanagement is honestly prone to backfiring.
I'd have preferred practically the opposite concept: increase shift requirements by 50% so everybody is working 8-hour shifts, with this improving Motivation when passed and reducing the Discontent penalty from making a jobsite work 24 hours.
Mind, I'd also have preferred more in the way of toggles. Why can't I run regular Two Shifts at some places and the Shift Work Coordination variant elsewhere? Why does passing this Law take away the old option forever? That doesn't make logical sense and it's not serving a clear gameplay purpose; this is in fact a bit of a recurring problem with The Last Autumn's Laws, that you have a fair few Laws that really should open up an additional option and instead they replace an existing behavior for no clear reason. The Adaptation and Purpose Laws in other scenarios largely avoid his type of jank; I'm not sure why this new problem haunts The Last Autumn.
Next Law!

Safety Procedures
Requires: Nothing.
Law Cooldown: 18 hours.
All Generator tab buildings gain the Safety Procedures toggle. While active, Safety Procedures applies a -25% Efficiency penalty, but raises Workplace Safety by 1. Passing this Law immediately raises Motivation a little.
Note that Safety Procedures usually acts as an additive modifier 'at the end': say you have 5 Workers on a building that accepts up to 20 Workers. That's 25% of the builing's potential, so they add 25% Efficiency. If you then activate Safety Procedures, this will (usually) subtract 25 from 25 and so the building will do no work, being at 0% Efficiency. I say 'usually' because sometimes it will randomly remove only 25% of whatever current Efficiency is, with no rhyme or reason I can determine (I think it's most prone to occurring when an Efficiency boost is in play?), but most of the time it does the additive penalty thing.
This notably means it's important to maximize Worker count if you want to leverage Safety Procedures. Applying it to a maxed-out worksite gives the expected 25% reduction in effectiveness, whereas applying it to a worksite that's only got half its maximum Workers means you're halving the speed that work occurs at.
It's really weird and I don't get why the devs did this. Except for Organ Transplants sometimes buggily adding 20% to what should be a 0% building, the only other Efficiency modifier in Frostpunk to do this addditive behavior is Automaton innate Efficiency: everything else is a percentage boost scaled to labor rate. (eg +20% makes each citizen at a Steelworks add 12% to Efficiency rather than 10% each) It's so weird I gnuinely wonder if it's a bug or oversight.
Aside this weird thing with its Efficiency, I quite like Safety Procedures as a Law and building ability. It works straightforwardly sensibly (outside the Efficiency thing), it's perfectly sensible that slowing the worksite down can make it less dangerous but also, y'know, slower, and it fits well with The Last Autumn overall trying to pressure the player into making unpleasant decisions bcause of their needs: you need to build the Generator on a timetable, so if you're falling behind schedule you're going to start getting a temptation to abandon caution and hurry things along at the cost of employee safety. It works nicely! Aside the Efficiency jank.
Next Law!

After-Hours Equipment Maintenancce
Requires: Safety Procedures.
Law Cooldown: 18 hours
Immediately raises Discontent some and applies a permanent Discontent increase, but unsafe workplaces will have lower odds of an Accident triggering.
Um, what?
Alright, first of all I should explicitly clarify this does not change the Workplace Safety number; all it does is make it so a workplace that is sufficiently unsafe that Accidents are possible will have nebulously lower odds of such an Accident occurring at any given moment.
This... makes it kind of awful. You can't tell if it's benefited you at all, and more importantly it's very viable to get through The Last Autumn having your workplaces largely or entirely at -2 Safety at worse; you have to be at -3 or worse for Accidents to have a chance of rolling. This Law also has absolutely no effect on the series of Accidents that are tied to specific steps of Generator construction and which occur when the given building reaches a specific percentage of completion. As such, you are largely suffering a Discontent penalty for absolutely no benefit, making this a dumb trap Law.
I'm also unfond of it from a more narrative standpoint. Proper maintenance of tools isn't already occurring? My employees being ordered to maintain their tools pisses them off and also doesn't tie up any of their time? Huh? What is this??
Next Law!

Dispensary
Requires: Nothing.
Law Cooldown: 36 hours.
Unlocks the Dispensary and initiates a quest to build one within 2 days.
The building!

Dispensary
Costs 30 Wood and 20 Steel.
Size 2x2
Manned at all hours by up to 5 Engineers. +1 Heat, supposedly does... something to help with Gravely Ill patients.
need to actually test the damn thing
patients prefer Infirmary
regular Ill people refuse to use the thing
really dragged down by needing to wait for Labour Laws to unlock, by how Gravely Ill is functionally impossible to see before work on the Generator starts, and by Infirmaries still being great
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Next time, we start getting into the real meat of Labour Laws, starting with siding with the Engineers.
See you then.