I think @Marostegui mentioned that the pt-kill patched version we maintain at WMF (T203674, T183983) for stretch works without change on buster. However, it would be nice to have an "upgraded" package, with an upgraded pt-kill version that either already fixes or may need a slightly different patch. It would also be nice to recheck dependencies, systemd mangement, etc. for the new version.
This would be a soft blocker for the labsdb* hosts upgrade to buster.
- Puppet related code: modules/profile/manifests/labs/db/kill_long_running_queries.pp
- Deb package source: https://gerrit.wikimedia.org/r/admin/projects/operations/debs/wmf-pt-kill