Based on my understanding of the devguide section, the backport labels cause miss-islington to attempt to perform the backport automatically after the PR is merged. Unless that functionality is changed, I think those labels should probably be reserved to the core devs.
Here’s the list of cpython labels, omitting awaiting, CLA, automerge, and backport:
DO-NOT-MERGE, expert-asyncio, invalid, OS-mac, OS-windows, skip issue, skip news, sprint, type-bugfix, type-documentation, type-enhancement, type-performance, type-security, type-tests
From that list, the ones I’m uncertain about for triagers would be DO-NOT-MERGE, invalid, (due to them coming across strongly) and potentially type-security. The distinction between a PR being type-bugfix vs type-security might not be immediately clear. As an example, I initially had assumed that this PR would have been considered a security issue instead of a bugfix due to it being able to crash the interpreter with a segfault.