The full paragraph reads, "In fact, the real story concerned just two drop-off adventure play areas, where parents had taken to hanging around and were being asked (by the Liberal Democrat council) to desist. It’s not that the country doesn’t have its jobsworths and back-coverers, who overinterpret regulations, health and safety rules or bylaws to suit their whims and fears. It always has had. In my childhood it was park-keepers."
The context gives the definition: those "who overinterpret regulations, health and safety rules or bylaws to suit their whims and fears."
In a cruder setting, we would say those who "cover their ass" by these actions, over-interpreting rules, etc., to protect themselves or (in the case of "jobsworth") make sure they are busy, or worth their pay grade.
Student or Learner