I don't think auto-merging is a compelling use case here anyway (especially with tools like [mergify](https://mergify.com/) available). I'm not sure we'd be able to prevent an especially determined repo maintainer (they can always make a task that does it), but at the very least I'd vote on not making this any easier (i.e, let's not directly support a `merge` comment).
Bug 1715848 Comment 5 Edit History
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> "merge" operations (and other that impact production code for sensitive repos) need to respect any restrictions configured in GitHub (e.g. collaborator may need to be on GitHub allow list) I don't think auto-merging is a compelling use case here anyway (especially with tools like [mergify](https://mergify.com/) available). I'm not sure we'd be able to prevent an especially determined repo maintainer (they can always make a task that does it), but at the very least I'd vote on not making this any easier (i.e, let's not directly support a `merge` comment).