The mirror list and the following links:
This list is from the home page of the site, but mirrored here for viewing purposes.
Back in 2018, the Internet Archive did not have browseable access to .tar archives' file contents (yet .zip archives' file contents were browseable), so you either had to download the entire ~220GB archive just to grab a few files, browse the at-the-time partially broken ftp.hp.com site, or accidentally discover a live former Compaq FTP site within HP's network (once resided on ftp://22.214.171.124/ and ftp://g2t3114.austin.hp.com/ but was yanked offline on July 2017), so I mirrored the .tar archive's contents to this server on May 9, 2018. Now it is possible to browse .tar archives' file contents on the Internet Archive so this is no longer an issue, though the sheer amount of files in that archive means it would take a while to load the entire list, so I left the mirror on this server as backup.
Regarding the ftp.hp.com mirror (compaq-extra):
On May 16, 2018 and January 7, 2019, I grabbed the following directories from ftp.hp.com precisely because they were incomplete on the ftp.compaq.com mirror: sp0000-0500, sp0501-1000, sp1001-1500, sp1501-2000, sp2001-2500. Technically, you are not supposed to access that site; however, HP still haven't shut off public FTP access for it nor bothered to remove any older files. Support for much older hardware are no longer on their site, yet most of the files remain if you know what to look for.
Regarding the ftp.fic.com.tw mirror:
I mirrored this site mostly on a whim in October 2015 and added it to my server the same month. I pretty much forgot about that mirror until someone on Twitter notified me about it. That same day, there was a thread on VOGONS about the FTP site no longer existing, and apparently I was the only one with the existing mirror. It was eventually added to the Internet Archive on March 17, 2020 as a secondary mirror.