I bought a Brother colour laser last year (which on the outside looks identical to the monochrome one I bought 17 years ago that lives with my parents), zero issues, which pretty much has been my experience with printers on linux (also tried a ~5 y/o & 25 y/o HP LaserJet, one being the cheapest thing I’ve ever used, other being old office equipment, think I tried the Epson ecotank and photo printer my mil has as well)
Afaik, almost every browser uses “Mozilla/5.0” as part of the user agent, Mozilla mentions it as well in developer docs about User agents, it’s a historical compatibility thing apparently.