TetraBB.com Home of Tetra-WebBBS and TetraBB PRO

: webbbs_text.pl ?

Yes. Language file. Considered a configuration file.
However, instead of editing text.pl it's much more maintenance friendly to use the custom_HTML feature and copy the text variables into an active custom.pl and have the edited variables there.
That'll overwrite what's initially set by text.pl and allows to simply replace text.pl with the next default file on upgrades but keep customization without redoing edits.

.... more than just one way to go.

Rainer