This would always move all keyframes

What would move all keyframes? This is a strange sentence to start with.

Apart from that nag, I can't really comment because I'm totally not familiar with the transform code. From a quick glance it looks headache-inducing (who decided that having both value and val is a good naming strategy?) but otherwise fine. The "there is AnimData" block already uses td->factor as a factor for value, so using it in the other case for val can't be all bad ;-)

In D6697#158163, @Germano Cavalcante (mano-wii) wrote:

This area of the code is buggy and much of it could be deduplicated.
Since you are working on it, I recommend snapping at the end, removing those if (autosnap == ...) lines and editing doAnimEdit_SnapFrame to call snapFrameTransform in these cases (SACTSNAP_TSTEP, SACTSNAP_STEP).

(Some variables could also be renamed to avoid confusion).

Since (at least moving the snapping) would alter behavior (and would not be just a "fix"): suggest to split this into multiple commits ([1]fix [2.82], [2]cleanup [master], [3]change snapping order [master])? (happy to do this)

In D6697#158223, @Germano Cavalcante (mano-wii) wrote:

In D6697#158166, @Philipp Oeser (lichtwerk) wrote:

Since (at least moving the snapping) would alter behavior (and would not be just a "fix"): suggest to split this into multiple commits ([1]fix [2.82], [2]cleanup [master], [3]change snapping order [master])? (happy to do this)

It's OK for me.

Pushed the fix now, will do proper Differentials for the other stuff...