Real ThinkPad keyboards (not this monstruous ignominy) have directly accessible keys for XF86Back and XF86Forward. That is really problematic with web browsers such as Firefox or Chromium since pressing those keys transparently go back or forward into your history, discarding anything you were typing in the process, including that 3 hours long bug report you were just about to submit. That’s rather annoying, to say the least.

Some other blog post suggest to simply disable them with xmodmap. That is in ~/.xmodmaprc (or whatever it is you use):

keycode 166 = NoSymbol
keycode 167 = NoSymbol

I personally prefer to remap them to Next/Prior keys. Having these near the navigation keys might come up handy:

keycode 166 = Next
keycode 167 = Prior

That’s on Linux though, on FreeBSD the keycodes are 233 and 234:

keycode 233 = Next
keycode 234 = Prior

Anyway use the xev command and xmodmap -pke to find the keycodes and remap them to any other interesting key symbol.