CC: Restitched Updated, is a fork of CC: Tweaked for Fabric (Discontinued), which is a fork of CC: Tweaked which ports the mod over to Fabric 1.16.5. It also aims to maintain feature parity with the official CC: Tweaked.
If you expirience issues, please open an bug report using the template provided on github, otherwise you more than likely will not get support regarding your issue.
ComputerCraft itself adds many different computers and turtle robots which can be programmed and used with Lua to perform various different tasks. Computers and turtles can both be extended with peripherals, which allows the computer to perform additional functions such as wired and wireless networking, printing, playing sounds, and more.
Turtles can also have tools applied which allow them to dig, mine, attack, hoe, and more. They are essentially one of the best tools for automating different in-world tasks.
For information on how to use the various APIs in the mod (as well as how to use the basics of the mod), you can check out the CC:Tweaked Documentation
Credits
DanTwoHundred - Original Author of ComputerCraft
SquidDev - Author of CC: Tweaked, which this port was based off of
Zundrel - The person who got CC:T For Fabric close enough up to date for me to start updating the mod