Easter Egg in Prusa XL Firmware? Or potential Leak?
TL;DR
In the update to the firmware for the XL, configurations for 2 other printers seem to have been added: Prusa MK404 and Prusa IXL. Here's a direct link to the code.
This all could be pure head cannon, "MK404" and "IXL" could just be other internal projects, or even just code names for parts of what makes the XL work. There's a lot of code for the mk404 that is related to the MMU I'm very new to the 3D printing world, and I've never contributed to a Prusa project, so I hesitate to make definite claims about what code in their repos means about things in real life. But honestly, this all *looks* like Prusa has been working on 3 printers this whole time, not just the XL, which may explain the XL's elongated development time.
MK404 could potentially just be an Easter Egg, and IXL could be an early internal name for the XL. I have no idea for sure, I'm just going off what's been commited into the repo.
Still, if these are just Easter Eggs or old internal names, there seems to be a lot of effort put into them.
The /include/marlin/ directory contains unique configurations for "IXL", "Mini", "MK404", "XL", and "XL Dwarf"
Now, to be completely fair, almost all of the content for MK404 and IXL seems to be copy-pasted from other files, they aren't exact copies, so some manual editing had to occur.
You can see the configurations for IXL and MK404 are nearly identical, but do contain some differences.
You can also see that CMakePresets.json includes unique configurations for these 'new' printers
Other interesting bits include GUI configs for "IXL" and "MK404", the IXL GUI config directly states that it's copy-pasted from the XL configs and notes that they need to fill in the real values later. Link to MK404 Link to IXL
Here's another reference to both the "IXL" and "MK404" as valid printer targets when building the firmware via command line:
Honestly, there are almost too many places to point at to show that these may indeed be real models of printers Prusa is working on. The commit that all of this info is included in is over 500,000 lines of changes, which is absolutely huge by any standard. Even with how much of the code for the "IXL" and "MK404" is clearly filler content, this commit must represent months of work by a very sizeable team.
I'd encourage anyone with any interest to clone the repo locally ( https://github.com/prusa3d/Prusa-Firmware-Buddy.git) and view it in VS Code/Atom/Sublime Text/etc, to try and learn more. That's the beauty of FOSS, it's all there out in the open.
I'll leave with some more screenshots of interesting stuff:
Best Answer by Walter Witt:
MK4 Released and shipping
https://blog.prusa3d.com/announcing-original-prusa-mk4_76585/
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
I'd almost assume "MK404" is a play on the HTTP code (404 - not found). IXL is interesting though. Internal XL?
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
Interesting find - thanks for sharing. I hope they are working on the Mk4.
--------------------
Chuck H
3D Printer Review Blog
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
I'd almost assume "MK404" is a play on the HTTP code (404 - not found). IXL is interesting though. Internal XL?
I had the same thought about the 404. Part of me feels like I'm getting excited over some internal easter egg. The people working at Prusa are clearly *very* good at their jobs, the code quality in the Buddy Firmware is great (I wish I wrote code this clean) and with the sheer number of references to 'IXL' and 'MK404' it feels unlikely that the people at Prusa just didn't notice that they left all this in for the public release.
Still, like I said before, the amount of code dedicated to these 'printers' makes me wonder. This looks like way too much effort for some 'April Fools' joke.
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
Oh! I wonder if IXL is the print farm version?
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
I'd almost assume "MK404" is a play on the HTTP code (404 - not found). IXL is interesting though. Internal XL?
If you want to see it: https://www.prusa3d.com/product/nothing 😉
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
Update:
After a bit of googling, turns out the MK404 is a printer simulator made by @vintagepc, so *not* a tangible printer. Not sure if this means the IXL is virtual too, although they do share some diagnostic code, as one of the screenshots I posted before show.
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
Yes it is: https://afs.prusa3d.com/ iX(L) was at some exhibition in Germany long time ago: 
Oh! I wonder if IXL is the print farm version?
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
I have noticed the same right after the release of XL Firmware, but the thing is, that this simulator MK404 is for 8bit and FW for MINI, XL is for 32bit, which is suspicious :))
Update:
After a bit of googling, turns out the MK404 is a printer simulator made by @vintagepc, so *not* a tangible printer. Not sure if this means the IXL is virtual too, although they do share some diagnostic code, as one of the screenshots I posted before show.
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
Sure, right away from the release of the MK3S+ 😉
Francky, a few years back there should have been more printers released, but then came covid, war, etc. We can only hope that the situation with el. components has improved enough to not prevent anything from launching new models...
Interesting find - thanks for sharing. I hope they are working on the Mk4.
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
Oh, good catch, I probably never would have connected those dots.
Good catch with the old 'iX' design on the old afs announcement too. My wife theorized that the 'I' stood for 'industrial', guess she was right, more or less.
I have noticed the same right after the release of XL Firmware, but the thing is, that this simulator MK404 is for 8bit and FW for MINI, XL is for 32bit, which is suspicious :))
Update:
After a bit of googling, turns out the MK404 is a printer simulator made by @vintagepc, so *not* a tangible printer. Not sure if this means the IXL is virtual too, although they do share some diagnostic code, as one of the screenshots I posted before show.
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
I think you are right. They will caught up on the XL and release news of the MK4 or what every they call it. I think they will stick with the current form. I highly doubt it will be a Core XY.
Sure, right away from the release of the MK3S+ 😉
Francky, a few years back there should have been more printers released, but then came covid, war, etc. We can only hope that the situation with el. components has improved enough to not prevent anything from launching new models...
Interesting find - thanks for sharing. I hope they are working on the Mk4.
--------------------
Chuck H
3D Printer Review Blog
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
Prusa Original i3 MK# line must be upgradable. So the next CoreXY could be a different model.
TBH, I would love to see a Voron printer with a touch of Prusa.
Prusa is already one of the main suppliers of Voron printer kits thanks to PrintedSolid.
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
I just noticed this on the Printables, do you get it too??
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
Yes.... But I guess that will be impossible to have another realese in the next months. Prusa have a lot to do with "just realeased" XL.
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
huh, yeah, I'm seeing that too.
You don't get any results when you search for Mk4 prints, but there still might be some fun metadata to skim off of these XHR requests, although odds are likely low. We probably need some sort of highly privileged user account to get any juicy data.
Still, I might just try crafting some requests when I get off of work, just in case.
I just noticed this on the Printables, do you get it too??
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
Not seeing it. Maybe an accidental exposure while prepping for an April fools prank? Didn't Prusa do something along these lines last year?
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
Yep, it's gone for me too.
Dang, I shoulda saved the ID they assigned to it.
Not seeing it. Maybe an accidental exposure while prepping for an April fools prank? Didn't Prusa do something along these lines last year?
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
I was not the only one:
Source: https://twitter.com/MultiTricker/status/1640372364180594688?s=20
RE: Easter Egg in Prusa XL Firmware? Or potential Leak?
I went back thru my browser history and checked, if anyone else wants to muck about and look for metadata, the code Printables assigned the `mk4` was "618"