Would it be possible to add the ComputerCraftEdu code to the 1.79 tag (making one mod out of two)? It is popular amongst my underage students but I would like to do some changes.

Changes I would like to do is for instance to never let beginners turtles halt on "movement obstructed" etc. They also need to be placed facing the player instead of away from the player. The number of lines in a program could be increased etc. The most obvious change would of course be to have the mod updated to a newer minecraft version.

I can't find Dan's tweet explaining this, but basically he doesn't have rights to the CCEdu code: it was developed for Teacher Gaming as part of MinecraftEdu, and so is now owned by Microsoft. It might be possible to get in touch with the MCEdu team to see if they'd be willing to release it, but I wouldn't count on it sadly.

Is an opensource clone an option?

I tweeted the link to this issue page to @PlayCraftLearn (https://twitter.com/PlayCraftLearn).

This is a real shame - I also have a bunch of features in mind to add; such as the ability to define functions, and to scroll infinitely either way - I keep running out of space atop the program, and then have to drag all the icons down, which is tedious.

I've left feedback at help.minecraft.net, referring to this issue. Hopefully they will follow up, and at least someone will be aware that Microsoft owns the rights to ComputerCraft.

I should also note that a possible way forward is to create your own visual code editor that you run alongside minecraft, which edits files in ~/.minecraft/saves/[yourworldname]/computer/[computernumber] (on linux), or somewhere in %APPDATA%/local/minecraft on windows. You could create a visual editor that supports functions, for instance, and has symbols also for 'while' 'for' etc. - for teaching a child who can't distinguish between text yet. At least the visual code editor could be fully customized that way.