This means autovacuum is doing it’s job — most likely no need to be alarmed here based on this alone. The autovacuum is helping avoid a txid limit. This is part of PostgreSQL MVCC. You may check that section of the documentation for more information on this.
I have autovacuum running in background from last 30-40 minutes but I noticed that it is with "(to prevent wraparound)" say for example autovacuum: VACUUM trk.move (to prevent wraparound).
So what is the meaning of "(to prevent wraparound)" here ?