Which character produces “%3Q” from urllib.quote?

问题

We're encoding urls with user-supplied data using python's urllib.quote(); one of the urls is producing a string with the following substring:

'%3Q'

I'm trying to figure out what the original user-supplied character is, but am getting stumped: I can't seem to find any resource that mentions the character that produces this output from urllib.quote(). Strangely, there are no results in stackoverflow with this string of characters.

It's also important to note that the user-supplied data is first piped through base64 encoding, and the result of that is then piped through urllib.quote()

Let me also add some clarification: I see the %3Q string in the GET request to a webapp; it's possible that urllib.quote() produced a string which was then modified by either an email client or browser before it made it to the webapp. It's possible that one of these is responsible for some sort of obfuscation post-quoting.

来源：https://stackoverflow.com/questions/37574004/which-character-produces-3q-from-urllib-quote