Here is a recent payload from stg.pagure.io

2019-09-16 13:41:05,532 DEBUG zuul.RPCClient: Submitting job pagure:stg.pagure.io:payload with data {'payload': {'msg': {'project_fullname': 'python-mock-distgit', 'pagure_instance': 'https://stg.pagure.io/', 'tag': '1.4', 'repo': {'close_status': [], 'url_path': 'python-mock-distgit', 'id': 471, 'tags': [], 'date_modified': '1558356006', 'priorities': {}, 'custom_keys': [], 'access_users': {'ticket': [], 'admin': ['zuulbot'], 'owner': ['fbo'], 'commit': []}, 'namespace': None, 'description': 'Copy for python-mock from src.fedoraproject for testing purpose', 'name': 'python-mock-distgit', 'date_created': '1558355896', 'access_groups': {'ticket': [], 'admin': [], 'commit': []}, 'user': {'name': 'fbo', 'fullname': 'Fabien Boucher'}, 'parent': None, 'milestones': {}, 'fullname': 'python-mock-distgit'}, 'authors': [{'name': 'fbo', 'fullname': 'Fabien Boucher'}], 'agent': 'fbo'}, 'msg_id': '2019-14a179e4-aca4-4c8d-b0f6-6033f89605aa', 'i': 95, 'topic': 'git.tag.creation', 'timestamp': 1568641264}}

I would like to receive the hash of the tag related commit.

See this patch where I tried to add the rev field: https://pagure.io/pagure/pull-request/4609