This closes #90727
However, the alternative is to move this information on top. I don't think it deserves to be a note (without providing a workaround) because you absolutely need to know this information to use this method properly.

Returns this basis's rotation as a [Vector3] of [url=https://en.wikipedia.org/wiki/Euler_angles]Euler angles[/url], in radians. To prevent unexpected results, the basis must be [i]uniform[/i] (all axes share the same length) (see [method get_scale]).

or, likely too subtle:

Returns this [i]uniform[/i] basis's rotation as a [Vector3] of [url=https://en.wikipedia.org/wiki/Euler_angles]Euler angles[/url], in radians.

Is uniform well-defined somewhere?

We have different definitions of uniform, uniform scale, orthogonal vs is only a rotation.

"Uniform" in this context is defined in Basis' leading description among others:

A [Basis] is [b]orthogonal[/b] if its axes are perpendicular to each other. A basis is [b]normalized[/b] if the length of every axis is [code]1[/code]. A basis is [b]uniform[/b] if all axes share the same length (see [method get_scale]). A basis is [b]orthonormal[/b] if it is both orthogonal and normalized, which allows it to only represent rotations. A basis is [b]conformal[/b] if it is both orthogonal and uniform, which ensures it is not distorted.

Side note, but that intro section might be clarified with something like:

A [Basis] is:
- [b]orthogonal[/b] if its axes are perpendicular to each other.
- [b]normalized[/b] if the length of every axis is [code]1[/code].
- [b]uniform[/b] if all axes share the same length (see [method get_scale]). 
- [b]orthonormal[/b] if it is both orthogonal and normalized, which allows it to only represent rotations. 
- [b]conformal[/b] if it is both orthogonal and uniform, which ensures it is not distorted.

I don't know if a split sentence like that translates well, though.

Lists are awesome but currently they take too much space in the built-in documentation because unordered lists are not supported. Each new line adds a whole other line to simulate a paragraph. When I made the PR originally I was probably accounting for this. But... sure

Ah, good to know. Unordered lists are used in a few places for parameters in method descriptions, but I think the vertical space is more acceptable there.

(They do render pretty well in the online class reference, FWIW)

Yeah, but that's accidental because - is not escaped and it conveniently denotes a list for that markdown format. We should still do "lists" like this for general consistency. Look at #88900 , too.

I believe this is the opposite ("When a variant is transformed by this constant")? This current text was derived from the original, rather vague statement.

I have already done the change as I feel confident about this.

I am heavily considering removing "It can be used to make your code clearer, and for consistency with C#." it feels... for granted, or perhaps not the right place for recommendations(?).

Instead, I wanted to mention how this is basically the default value for Basis/Transform2D/Transform3D/Quaternion

Reason why "and its scale being [code]1[/code]" was changed is because, nitpicky, it's technically incorrect. The "scale" is Vector3.