It metaphorically means that one is able to do things independently or no longer obey others, which is often used by the elder to juniors or people with experience to the other inexperienced ones.

通常是长辈对晚辈，或者在某方面有经验的人对没什么经验的人说的话。

youdao

Some of the more senior ones act as brokers for their juniors' forced labour on building sites or in the fields.

ECONOMIST: A cold, hungry, pointless Russian army