this happens only in this one terminal window
and only the shell is affected, i can’t even type # without it appearing as £
opening this file in vim is fine though!
TIL: there is an escape sequence that makes a line wide (\e#6), which Konsole apparently understands

@whimsy I just noticed that I've never replied to this -- sorry for the delay ^^
basically I discovered them while investigating the alternative charset thingy from the opening post where my # includes were replaced with £. eventually it lead me to discover vttest, a tool for testing terminal (emulator)s from the xterm maintainer. while running it I noticed that some tests displayed wide and large text -- something I've never seen before in a terminal window!
thankfully the source code of vttest is relatively easy to grep through, which finally led me to these escape sequences