Is allow partial indices a valid option snapshot option?

In 7.4.2 I noticed that SLM has a snapshot policy option of "Allow partial indices". I noticed in the snapshot and restore documentation this option is not mentioned anywhere (link to docs)

Although if I add it to a standard snapshot command the snapshot runs fine.
PUT /_snapshot/test-snapshots/test_snapshot
{
"indices": "*",
"ignore_unavailable": true,
"include_global_state": false,
"allow_partial": true
}
Is this new option available to normal snapshots not controlled by SLM?