post
{scheme}://{server}/v0/message-groups//restore
Restore all previously-trashed or quarantined messages in a group and turn off automatic trashing/quarantining of future messages in the group. "For an Office 365 message source, each message will be put back in the folder it was in before. For a Google Workspace message source, any applied labels (e.g. "Trash") will be removed from each message."