Programming and reading.
Not quite correct. For html, that is to signal standard compliance, you can leave it away and the browser will still handle it. For the bash one, all (most) shell scripts use .sh, so you need to give a shebang to tell the loader which executable (sh, bash, zsh, csh, …) to use
Also on Linux xdg does take file extensions into account, just executables do not
It’sintended to be used when the cookies are actually required for the app to work. For example, to preserve your login, you need a cookie, no way around. Unfortunately, as mentioned by others, it’s often abused
Jerboa doesn’t have anything to do with it, it is the app you use to access the fediverse/lemmy.
Lemmy has upvotes, downvotes and the tally of those two. Karma is a step further; on reddit, every user has a total tally (Karma) as well, where all up/downvotes of every comment and post are added together as a “score” for the user. So people post popular stuff to get upvotes and thus have a higher score (which some subreddits required to post).
This would likely only hurt the end user. Many use chromium-based browsers, so you’re just driving those away.
You can detect Firefox, so you can do a superficial block in JS, but lemmy is such a simple site that you’d find it hard to find areas where there’s actual differences between the browsers, those usually only come from complex pages like video calling