@martinschlegel @Extelec Pretty much any version of #NetBSD should run on a #ThinkPad T23 out of the box, and #pkgsrc will include the ~latest #firefox. I tested it on a ThinkPad T41, which is only two years more recent than the T23 - https://youtu.be/jYS4TcgxMxU
Now, whether you can do anything *useful* in modern Firefox on a 1GB 32 bit machine... not so much
#PaleMoon or #ArcticFox are pretty capable browsers which run well on smaller machines - and #Dillo will *scream* on that spec hardware 