RFR: Move jmx-dev files to serviceability-dev

[Iris Clark]

On Mon, 16 Feb 2026 11:33:52 GMT, Kevin Walls <kevinw at openjdk.org> wrote:

> The jmx-dev group is being dissolved, merged into serviceability.
> Please review this update to the mailing list rules.

Thanks for the follow-through related to the recent JMX Group dissolution (https://mail.openjdk.org/pipermail/gb-discuss/2026-January/000389.html).

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Marked as reviewed by iris (no project role).

PR Review: https://git.openjdk.org/skara/pull/1751#pullrequestreview-3809681862