Why are Linux Laptop Sellers so Secretive?
Hardware
When I was writing my article on my Starbook VI, I started writing a small side note on my annoyances with finding a Linux laptop seller that actually makes the laptops they sell, as opposed to a Linux laptop seller who buys the chassis from a manufacturer and calls it their own. And that side note turned out to be just as long as the article, so I split it off into a new article.
So when I think of the word "manufacturer," I think of someone who designs and produces a product. Now a laptop manufacturer doesn't necessarily need to manufacture every single wire or screw, or even design and manufacture every single board or chip that goes into a laptop. But I would think that to call yourself a laptop manufacturer, that it would entail that you at least put in some work on how the laptop is designed and put together, more than just which sticks of RAM, which hard drive, or which CPU to stick into the respective slots. Otherwise I could call myself a laptop manufacturer by just buying Dell laptops and upgrading the RAM.
So when you look at for example, System76, you go on their website and look at the laptops they have to offer, you might assume that they design those laptops themselves. But they don't! And you wouldn't have any idea that they're selling Clevo laptops from looking around on their website. I looked on their about page, and they say this:
System76 proudly engineers and manufactures premium Linux computers and keyboards at our factory in Denver, Colorado.
Maybe they don't consider laptops to be computers? Or maybe they consider installing RAM and hard drives manufacturing. Either way, I disagree with them calling themselves manufacturers, at least with respect to laptops. I would at most call them laptop assemblers.
I looked all around their website trying to find any references to Clevo, and I couldn't find any. I did a search on their website, and came up with 0 results.

I finally did a Google search limited to their website for the keyword "clevo", and I came across a single result on System76's website. A blog post referencing some git commits regarding audio quirks on Clevo boards. That's it.
When called out on social media, they do own up to being sellers of Clevo laptops, and then give some justifications for it. But it puts a bad taste in my mouth when they're not being upfront about who is actually behind the laptops they are selling.
Same thing with Tuxedo Computers laptops. Search on their frontpage for Clevo or Tongfang and you find no mentions. Look on their Why Tuxedo page, no mention of the previous two laptop manufacturers either. The only mentions I was about to find on their website were in user reviews, and I had to do some exact phrase Google searches for those too. Additionally, they also say that they "manufacture" computers on that page.

Again I would call that "assembling" a laptop, not "manufacturing" a laptop. Let me put it this way, if I bought a Honda Civic with no wheels, and installed wheels on it, that doesn't make me a car manufacturer.
A side side note on Tuxedo's name
It looks like Tuxedo likes to stylize their name like TUXEDO. But I don't like that. It reads to me like I'm yelling TUXEDO!!! As if I'm really excited about the Tuxedo laptop brand for some reason. I'm not, so I'm not going to stylize it.
Back to laptop "manufacturers" and Tuxedo
When Tuxedo was asked on social media what actual type of laptop they're selling, they're even more secretive than System76. In that comment thread, a Reddit user asked
is this a Schenker laptop? ...
and someone who appears to be a Tuxedo representative answers later in the comments only that
... this time it's not a Tongfang
Okay well who is it from then dammit? Why is Tuxedo so secretive about who they are sourcing their laptops from? They also said later in that comment thread that they worked exclusively with a factory. What factory? That's not answered. They admitted that they once sold Tongfang laptops, but that's it.
Compare that with other sellers of Linux laptops. If you go to Slimbook's frontpage, you won't see any mention of the actual laptop manufacturers. But they don't claim that they're a laptop manufacturer either. At the bottom of the front page they say
At Slimbook we assemble our devices in Spain, where we generate work and pay taxes, with finishes and components from the best hardware brands.
I like that they're honest about their role. And also if you go to their about us page, they're even more clear
If you are wondering where our computers are manufactured, the best thing to do is to see a presentation we made at the UNED in 2015. But remember that all brands manufacture in Asia, the difference is that we finish assembling them in Spain, with the language of the keys, hard disk, memory, etc, giving work here. The factories are OEMs/ODMs of first level like TongFang, Clevo or Compal, who work for brands like MSI, HP, DELL, etc. And although we are not like Apple and can't invent, we hire top quality components and finishes, improving manufacturing to the highest levels. And over the years, we've taken the word to the Linux kernel developers, to the big factories.
Completely open about what their role is, and I appreciate that from them. And if you go to Laptop with Linux's website and scroll down a little bit, it's even more obvious who's making the laptops.

Right there in the name. Three Tongfang laptops and one Clevo. They even have an All About Clevos section on their website.
Who Actually Manufactures Linux Laptops?
First, It's important to define what actually constitutes a manufacturer. I'll flip it around though, and define it as: Who is the gatekeeper of the laptop features? Let's say System76 would say to Clevo, "Hey we would like to have four usb-c ports on our laptops, two on each side." If Clevo would say "No, we're not interested in producing a laptop with those specifications." System76 would be shit out of luck. They could try to go to Tongfang or some other manufacturer, but at the end of the day they're at the mercy of the producers.
If Lenovo wants a laptop with 2 usb-c ports on either side of a laptop, they will design the laptop, then send the design to be fabricated in China or wherever they have their chips fabricated. Then they'll assemble it and sell it. Therefore, I would consider Lenovo a manufacturer.
Manufacturers
Two big names that I know of are actually Dell and Lenovo. In my experience in the past, they would only occasionally sell laptops with Linux preinstalled, and only usually with Ubuntu as the only distribution as well. But going on each of their websites it seems today they're offering a consistent and decent selection for laptops with Linux preinstalled. And that's nice too because you can get a decent discount for purchasing a laptop without Windows. In the past you used to have to pay the Windows tax regardless of whether you actually wanted to use Windows or not.
If you don't want to go with a big name brand, the two biggest manufacturers that I know of that have a larger focus on Linux laptops are Framework and Starlabs.
Framework is a company based in San Fransisco, and was founded in 2020. Framework laptops seem a little pricey for what you're getting. Doing some brief and informal searches on laptops with similar specs to the the Framework, I'm able to find some ASUS laptops that are several hundred dollars cheaper and even come with a dedicated Nvidia graphics card, if that would be something you're interested in. But the plus side with Framework though is that you're able to repair and upgrade your laptop in ways that you can't with other manufacturers. You can upgrade the CPU in a Framework laptop by replacing the mainboard, can't do that with most other laptop brands.
The other manufacturer is Starlabs, a company based in the United Kingdom and started in 2016. When they first started, they sourced their laptops from Clevo. But after a couple years they decided to start designing their own laptops. They also say in their about us page
It always perplexed us that a laptop had never been made specifically for Linux. Whilst many had been "converted" to run Linux - they seldom offered the experience that macOS and Windows users had. So, after a few pints, we decided to make one.
Like I mentioned at the beginning, I purchased Starlabs Starbook and I wrote about it, and I can definitely say I'm having a much better experience than Windows users. But a Starbook offering the same experience as a MacBook? No, there's still much to be desired. But Apple sets a very high bar with respect to quality, and I hope Starlabs can keep getting closer to that standard.
Honorable Mentions
Now I wouldn't recommend either of these laptop brands to people who aren't enthusiasts, but I'd like to mention MNT and Pine64.
MNT offers the MNT Reform, and ultra hackable open source laptop. It's somewhat more modular than the Framework laptops. But some problems with it are that it's enormous, kinda pricey, and you can't upgrade the CPU and RAM separately. The Reform incorporates a System on a Chip (SOC) in it's design. a SOC is a computer chip that contains all the necessary components for a complete computer system, kinda like the chip for a smartphone. Both the RAM and CPU are on this SOC, so that's why they can't be upgraded separately. But if you really like tinkering with hardware, and don't mind the price, this might be a laptop for you as everything in this laptop is open source.
Pine64 offers the Pinebook Pro, another open source laptop. It's pretty cheap, and a refurbished laptop from their website goes for a little under $200. But with a quad core ARM processor and 4 gigabytes of RAM, you're not going to be doing that much on this thing. I actually purchased one to play with for a little bit because it's so cheap, and I definitely wouldn't recommend it if you're not an enthusiast. The battery literally takes 12 hours to charge using their charger, and then it lasts 30 minutes playing a YouTube video. I'm really not exaggerating, that's my first hand experience. It's really rough around the edges. But it looks sleek with it's metal shell. I think it's a really cool laptop from a cool community so I thought I'd mention it.
Why Choose a Linux Laptop Manufacturer?
So why choose Framework or Starlabs over System76, Tuxedo, or the rest? Why choose the two companies that I define as actual manufactures over the companies who I would consider laptop resellers or laptop assemblers? The modularity of Framework laptops is one specific thing, but I personally don't care for that level of modularity. I will just purchase a whole new laptop when the time comes. But another thing I ask is, who is most likely to produce a very high quality laptop in the future? Laptop sellers who sell rebranded Clevo or Tongfang laptops can only go as fast as Clevo and Tongfang innovate. They won't be able to sell, maybe for example an ARM laptop like Apple does, unless Clevo or Tongfang offers it first. Tuxedo seems to actually be making progress on writing software for an ARM laptop, but they don't have a set release date and I can't find any mention of who is actually making the laptop.
I don't know how fast Framework or Starlabs will be able to make a laptop that would even approach the level of quality and power of a MacBook Air with an M4 processor, but I think they're much more likely to get there than the others. But that's just my reasoning. If you're a big fan of Pop!_OS, then you could support System76 by buying their System76 branded Clevo laptops. Or maybe you're Spanish and want to support Spanish companies, so you could buy a Slimbook branded Clevo laptop. Or maybe you just want a high end Nvidia graphics card, so you could buy a Tuxedo branded Clevo laptop (or whatever mystery laptop brand it is). But for my money, with laptops that perform similarly at similar price points, I'd prefer to support actual laptop manufacturers.