Problem characters in permalink urls?

I can't be certain without looking at the code and testing different browsers, but it appears that the permalink URL's need to be further %-escaped to be useful. It appears that LT / GT symbols are correctly %-escaped. Although they are displayed as symbols in the human readable chrome url bar, right-click/copy url does the right thing here;

https://lists.apache.org/thread.html/cd6e60a4f86c327e1d25994c4f3ef4f5cb37dfc5a33524461cf47d2a@%3Cannounce.apache.org%3E

Pasting this link into facebook, their parser split the URL at the '@' symbol, which falls in the set of gen-delims, and should be expected to confuse some parsers. Replacing AT with a %40 sequence allows the full link to be parsed, and the resulting url is handled correctly by ponymail.

My table of http vs. uri rfc characters is here, if you wanted to look for and escape other possibly confusing patterns;
https://docs.google.com/spreadsheets/d/1y5tENm_L8m0tV5iJHPfg9pQoBTeyjCB8JxwkNEwuH44/edit?usp=sharing

Start by reproducing the permalink behavior with the example URL and checking how it is parsed after copying or pasting into another service. Identify where permalink URL encoding is produced, verify handling of the @ character and other problematic URI characters, and consider the issue done when the complete URL remains parseable while still being handled correctly by Pony Mail.

Written by the indexing model from the issue text.