I'm concerned about it breaking 4.4 of the ToU.

Terms of Use wrote:

You may only submit user-generated projects that were created with (1) the Scratch website editor or (2) an unmodified copy of the Scratch editor compiled from the source code described in Section 5.3. You may not upload any projects that were created, by you or by anyone else, with a modified version of the Scratch editor.

Doing so technically does break the Community Guidelines, but it's not really enforced. Keep in mind that if the Scratch Team does decide to take it down, though, they have every right to do so.

MythosLore wrote:

Doing so technically does break the Community Guidelines, but it's not really enforced. Keep in mind that if the Scratch Team does decide to take it down, though, they have every right to do so.

Thanks.
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MythosLore wrote:

Doing so technically does break the Community Guidelines, but it's not really enforced. Keep in mind that if the Scratch Team does decide to take it down, though, they have every right to do so.

Yea, I’m not sure how people would tell in a lot of cases if it wasn’t stated, and that section is confusing because it sounds like it blocks people from using 2.0, or the 3.0 offline editor.

TW's documentation has a page about this. TL;DR I don't think the rule was ever enforced so yes, but you shouldn't require people to use TurboWarp (including custom extensions).

I'd say that it's fine as Turbowarp is licensed under the CCO 4.0 license and scratch is just down 1 version (CCO 3.0), but that'd require crediting of some kind….