This is the 1555th most frequent Russian word.
рабочего
"Рабочего" means "of a worker" or "worker's" in English.
Here, "рабочего" is the genitive or accusative singular of "рабочий." It indicates a worker as the direct object of the verb "увидел."
Я увидел рабочего возле здания.
I saw a worker near the building.
In this sentence, "рабочего" is a form of the adjective "рабочий," modifying "часа" and means "working hour."
Проект рабочего часа еще обсуждается.
The project for the working hour is still under discussion.
The word "рабочего" functions in the genitive singular and refers to a worker, showing possession to "уровень профессионализма."