Undo history limit and memory release behavior

The goal is to understand how GIMP manages memory for undo history when the user‑configured undo limit is changed.

Increasing the limit allows more steps to be stored, but observations show that memory allocated for steps that are later discarded beyond the limit is not released, causing RAM usage to stay high even after many undos.

It is unclear whether this behavior is intentional, if it constitutes a memory leak, or whether a hidden preference or environment variable exists to trigger reclamation of those discarded undo buffers.

1. Is the retained memory for discarded undo steps an intended design choice?
2. Are there any configuration options that enable automatic memory release when the undo limit is exceeded?
3. How can users reliably test whether memory is freed after undoing steps without altering the limit?