[polynomial]

Where did his 3,675 reputation come from? He only asked 2 questions and has a small number of badges.

[shagie]

You keep reputation on sufficiently old, sufficiently voted posts even if they are deleted.

Presumably, there are also deleted questions or answers that were up voted.

Additionally, there was a "up votes on questions are also worth 10 points" recently (past few years).

[scandinavian]

His questions have 444 upvotes, so he should actually have 4400 rep. He lost some to users being deleted. Looking at the reputation log he actually has less than he should have, but I'm not an expert.

[w-m]

Missing rep could be explained by the daily reputation limit of 200. Many upvotes on the same day when the questions get linked from news articles and discussions like this, only will count until daily cap is hit.