These files are for a legacy updating system. This updating system would only apply to users who have not used youtube-dl for at least a year (because if they did use it, they would notice that basically everything about every service, maybe except a couple of YouTube videos, has changed in between).
We often get commits including these files, and they are irritating for us core developers as well. Good riddance!
If anyone notes that their updates fail, they can just reinstall (see http://rg3.github.io/youtube-dl/download.html for instructions).
On 2.x, we now try TLS first, and fall back to the compat 23 (basically anything) afterwards.
On 3.4+, we now use the proper function so that we get all the latest security configurations.
We allow SSLv3 though for the time being, since a lot of older pages use that.
On 3.3, we default to SSLv23 (basically "anything, including TLS") because that has the widest compatibility.