My semi-educated guess is that the GUI tools in question are just wrappers for good old command line utilities, and that they pass the filenames to it without proper escaping, so the hashes get interpreted as comment symbols.
I mean…most likely it’s something stupid like that 
It’s kinda like when devs doesn’t wrap all their paths in quotes…some of us use spaces, you know 
Let’s free # !!! 
Wonder what happens when @Kresimir writes some dir names on Egyptian 
OK, I’m trying to reproduce. I assume you do a
mkdir -p ~/This\ is/#\ Only/A\ test
You open Dolphin in ~. What’s next?
I’ve never used the Egyptian hieroglyphs as dir names, but I do have directories named like this:
Pics of 🐸
More 🐸
Even more 🐸
ᚠᚱᚩᚷᚷᛖᛋ
etc…
No issues, except they don’t render properly in the TTY…
I have to ask… which is your favorite frog photo?
I mean, all of them are beautiful, but you must have a favorite, right? 
Impossible, it’s like asking a parent which is their favourite child 
True, they’d never admit to having one 
Go to that path, then:
2. Enter edit mode
3. Hit apply aka “Click for Location navigation”
That’s the easiest way to reproduce
I guess we have a solid proof that # ain’t nothing compared to and ᚠᚱᚩᚷᚷᛖᛋ
Linux devs just hate #
Ah, it didn’t click for me yesterday. So essentially “manually enter a path with an # and hit enter” in any plasma path widget.
I assume the # is treated special as an URL fragment indicator, which the file path widget doesn’t account for. A quick search shows existing activity in this area, e.g. https://invent.kde.org/frameworks/kio/-/merge_requests/167 or https://bugs.kde.org/show_bug.cgi?id=418711
Looks like an alien language 
Love it!
Nate Graham 2020-10-28 16:10:03 UTC
Works for me with git master KIO; this was a recent regression in KIO which has been fixed now. Will be released with Frameworks 5.76. Sorry for the trouble!
It’s just ordinarie futhark:
NO! It’s the AAAAAAALIENS maaaaaaan 
@keybreak Someone needs to step away from their source of caffeine.
I wish caffeine was enough to make me believe in aliens.
I am an Alien!