ROT47
ROT13 for the punctuation crowd.
Where it came from
ROT47 is a twist on ROT13 from the Usenet/IRC era: instead of shifting only the 26 letters, it shifts all 94 printable ASCII characters (codes 33–126). The joke is the same — obfuscation, not security.
It became a quick "make this unreadable at a glance" trick for source snippets and chat, since numbers and punctuation get scrambled too.
How it works
Each character in the 33–126 range moves 47 positions forward, wrapping around that 94-character window. So letters, digits and symbols all rotate together.
Like ROT13 it is self-inverse: apply it twice and you are back. UWC applies ROT47 to any printable ASCII in your browser, instantly.