Apply Modifier
Create an Apply Modifier that takes the current object modifier stack and makes it editable at that point. For instance, adding a subdivision surface modifier to a cube, followed by the Apply Modifier would work exactly as if the subdivision modifier was applied. As a modifier, you could turn the apply effect on or off.
3 Comments
Do you mean like the edit mesh modifier included in the modifier list extension?
If so, it was proposed many times on RCS already. The following post alone has already 12 duplicates listed: Edit-Mesh Modifier
Plus something similar might be implemented in geonodes eventually, see Data slots here: Geometry Nodes Workshop 2022 — Blender Developers Blog
This seems to contradict the operational logic of the modifier stack, and might cause additional data block caching or something. But I'm not a professional developer, so maybe it's not actually that difficult?