the regular cPanel actually allows via GUI to redirect a URL to another URL which contains the # character.
That # is neat in that it keeps every string behind # local. in other words, the remote webserver does not know about the trailing # stuff.
for a working demo click the link: http://wikileaks.is-great.org
here is a good application: Zero_Bin keeps the crypto key from the URL strictly local after # - meaning the server cannot hand over your key to any 3rd party such as … you know who. 
Ideally, infinityfree might consider lifting the # restriction unless there are legit reasons for keeping it.
So essentially, you now run your own URL-shortener like bit.ly is an example of.
example:
wikileaks.is-great.org redirects to https://0bin.net/paste/wFjDSfmQw2NYapIg#a9Xtuyp5IyiR281WAwS-5CNlYslKHiPd8aqNKvb0Zz6
If you use cPanel to configure that redirect, it will often times reject any URL containing # for spurious reasons. So in order to achieve the trick one has to manually edit the .htaccess file via ftp or the filemanager from cPanel such that e.g.
wikileaks.is-great.org/htdocs/.htaccess
contains