Is there a document explaining the tech spec of a hashtag?

[hiteshsharma]

The regex is very long and is very hard to understand

[andypiper]

The main documentation for our parsing is here, however it doesn’t specifically call out hashtags. What are you interested in, whether or not a hashtag is just a term starting with a hash/pound character, or other things?

[hiteshsharma]

When I see the regex, it seems there are rules for termination characters and there are some lookbacks as well. I was just interested in reading these rules somewhere rather than trying to parse that regex because I doubt I'll get it right if I simply start reading it.
Even if the regex is straightforward, it might still be a good idea to pen down the rules and specification of a hashtag somewhere, similar to how character definition is explained in the doc that you shared.