I know that Minecraft isn't shutting down. I was just wondering about what would happen to accounts (signing in, making new ones) and skins (would you have to download a mod what connects you to a third party skin server?)
As far as skins go, if you play an older version, such as 1.6.4, as I do, you already haven't been able to use online skins for years - I simply solved that by replacing the skin inside the jar file, which can also be done indirectly with a resource pack (I replaced the skin in the jar as I mod it anyway, same for the handful of textures I changed. I also originally did this so I'd still have my skin if the servers went offline - I never knew that they were permanently down until somebody else mentioned it). I've even exploited this by adding it to TMCW as sort of a signature, along with providing a basic resource pack for changing the skin.
Likewise, I don't have any worries about being unable to play if the authentication servers are ever shut down - the game itself doesn't require a login, only the launcher (for a year or so 1.6.4 couldn't even recognize a valid session ID due to MCL-7282 - I never noticed it). Not only that, Mod Coder Pack and other mod development environments (e.g. Forge) actually let you play without logging in; you do get a randomized username but that is easy to fix by editing the line of code that sets it (which I've done so I can easily test things that involve statistics). Of course, you can't play multiplayer (which I've never played so that isn't an issue), and you have to use the launcher to download the game files in the first place (presumably why Mojang allows this).
It is even possible to play versions older than 1.3.1 without any restrictions in singleplayer (aka demo mode) since they didn't add in the necessary code until then (demo mode is enabled with a command-line argument passed in by the launcher); Mojang has to know about this but probably figures that they are so old as to be demos in themselves, and very few players still play them either way:
Also, it is legal to modify a game you bought in order to bypass online authentication (only for singleplayer, it is also still illegal to distribute copies):
Now thanks to the US Copyright Office’s ruling this week, games that have a single-player component that requires online authentication to access can be modified or copied if the publisher has formally shut down the servers for longer than six months.
Unfortunately, this ruling only covers single-player components. It is still technically not legal for users to modify or copy multiplayer content, even after publishers abandon the servers. This is something that the EFF was fighting for but couldn’t quite achieve.
(I certainly would not wait 6 months, not that it matters for me due to the aforementioned reasons; the launcher should also let you keep playing as long as you never log out, keeping a backup of the .minecraft and Program Files\Minecraft folders)
(I certainly would not wait 6 months, not that it matters for me due to the aforementioned reasons; the launcher should also let you keep playing as long as you never log out, keeping a backup of the .minecraft and Program Files\Minecraft folders)
How do I backup my login?(Which reminds me that Steam has a ClientRegistry.blob file that you can backup and use to stay offline forever.)
I know that Minecraft isn't shutting down. I was just wondering about what would happen to accounts (signing in, making new ones) and skins (would you have to download a mod what connects you to a third party skin server?)
I think you don't need to think about shutdown.
It's still popular game, still has many people buying it, it's still working for new stuff,... 
As far as skins go, if you play an older version, such as 1.6.4, as I do, you already haven't been able to use online skins for years - I simply solved that by replacing the skin inside the jar file, which can also be done indirectly with a resource pack (I replaced the skin in the jar as I mod it anyway, same for the handful of textures I changed. I also originally did this so I'd still have my skin if the servers went offline - I never knew that they were permanently down until somebody else mentioned it). I've even exploited this by adding it to TMCW as sort of a signature, along with providing a basic resource pack for changing the skin.
Likewise, I don't have any worries about being unable to play if the authentication servers are ever shut down - the game itself doesn't require a login, only the launcher (for a year or so 1.6.4 couldn't even recognize a valid session ID due to MCL-7282 - I never noticed it). Not only that, Mod Coder Pack and other mod development environments (e.g. Forge) actually let you play without logging in; you do get a randomized username but that is easy to fix by editing the line of code that sets it (which I've done so I can easily test things that involve statistics). Of course, you can't play multiplayer (which I've never played so that isn't an issue), and you have to use the launcher to download the game files in the first place (presumably why Mojang allows this).
It is even possible to play versions older than 1.3.1 without any restrictions in singleplayer (aka demo mode) since they didn't add in the necessary code until then (demo mode is enabled with a command-line argument passed in by the launcher); Mojang has to know about this but probably figures that they are so old as to be demos in themselves, and very few players still play them either way:
https://minecraft.gamepedia.com/Demo_mode#Trivia
Also, it is legal to modify a game you bought in order to bypass online authentication (only for singleplayer, it is also still illegal to distribute copies):
(I certainly would not wait 6 months, not that it matters for me due to the aforementioned reasons; the launcher should also let you keep playing as long as you never log out, keeping a backup of the .minecraft and Program Files\Minecraft folders)
TheMasterCaver's First World - possibly the most caved-out world in Minecraft history - includes world download.
TheMasterCaver's World - my own version of Minecraft largely based on my views of how the game should have evolved since 1.6.4.
Why do I still play in 1.6.4?
I didn't say that it was going to shut down, and yes, I KNOW THAT IT WILL NOT SHUT DOWN ANY TIME SOON.
Think about it, Fortnite is almost dead (which is good) and Minecraft is still one of the best selling games of all time.
How do I backup my login?(Which reminds me that Steam has a ClientRegistry.blob file that you can backup and use to stay offline forever.)