This tool can be used to extract the Messages (and some other useful content) from a local Teams installation. It requires no extra privileges or access to any server, since it just accesses your local Teams "cache".
python3 utils/dump_leveldb.py -o teams.json -f .../Application\ Support/Microsoft/Teams/IndexedDB/https_teams.microsoft.com_0.indexeddb.leveldb
./decode_teams.py teams.json
The first command reads & parses the teams "cache" levelDB.
You need to specify the full path to that directory. It's location may vary depending on your OS, but dhe directory in question should always be called https_teams.microsoft.com_0.indexeddb.leveldb.
It's output will be a file called teams.json with all the decoded contents in machine readable form.
The second command will read the teams.json and convert it into human readable files in the specified output directory (defaults to conversations/).
The output consists of one file per Chat/Meeting/Space/Topic you participate in, which should contain a human readable plaintext version of your conversations.
You may also get a Thread_* file which contains a log of all your recent calls and a Conversation_* file which will contain a log of all recent notifications sent to you.
Original work on parsing the LevelDB files from https://github.com/cclgroupltd/ccl_chrome_indexeddb and https://github.com/lxndrblz/forensicsim.git