I'm not sure if Archive.org has a non-US copy of those, I'll take a look. Unfortunately most of my copies of OS/2 (any version) are US even though I live in the UK because I've purchased them over the years on eBay.
Every once in a while, I will take a peek at ebay.co.uk just to see what's out there, and still find copies of UK releases on there from time to time. I don't doubt, though, that US releases are far more common in the wild.
OS2LDR.MSG appears to be human-readable versions of various system messages and error codes, and does seem to be localized to the language of the region. Interestingly, it only makes an appearance on the Installation (boot) Diskette and not on Diskette 1, so the whole thing is getting slurped up into RAM at boot (by bootloader, or by kernel?). Haven't dug in deep enough to determine if this file just contains human-readable boot messages, or more than that.
The OS2World.com Wiki appears to have a screenshot of a non-US English (possibly UK) version of Warp 3
on the main page for the article on Warp 3 (right side). The fidelity of that particular screenshot isn't great, but you can at least make out that it's in English but omits the US Government GSA ADP Contract language below the copyright statement.
I downloaded Installation Diskette and Diskette 1 images from
this Internet Archive upload of a German Warp 3 copy, and booted them.
Here is a screenshot of what the boot screen for this German release looks like. The English copyright statement at the beginning is retained, but an additional German copyright statement is located where the US Government GSA statement is located on the US release.