The Compaq and HP stuff has a reference .txt file for some of the earlier SoftPAQ files (up to around 23000, though some of Compaq's stuff will need the site archive as reference), but for HP-era ones past that, you will need some archives of HP's website as reference regardless, as HP pretty much got rid of a bunch of old info around 2020.
How the firmware was accidentally discovered in the Compaq FTP mirror was after cross-checking the archives for the v1.13 firmware (thanks to Horun), I searched for the cp004707.exe firmware file on Google and my mirror showed up in the search results. This does work at times for other Compaq files (usually SoftPAQs).
The cwcyrix mirror from May 2018 is mine (home server since 2005/2006 😉); the only other known mirror from February 2021 is: https://ftp.zx.net.nz/pub/archive/ftp.compaq.com/
The original Internet Archive page for ftp.compaq.com is: https://archive.org/details/ftp.compaq.com and the .tar file is ~220GB. Browsing that through the Archive would really lag up the browser due to the very large directory tree, so it was just easier to mirror it. Since I know of only two mirrors, someone else should mirror it if they are able to.
For browsing FTP servers nowadays, you'll need the SeaMonkey browser or a real FTP client. But, HP's current FTP servers no longer have these files. (The SoftPAQ subdirectory there is still being used today!)
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So my earlier statement, the 'Compaq drivers weren't on the FTP server' was very wrong; it just wasn't in the SoftPAQ subdirectory (where most people would download from anyway), but rather the /products/servers/supportsoftware/ directory path.
Site update: cwcyrix.duckdns.org -> cwcyrix.nsupdate.info due to the former no longer working.