What verb form is してきた?

Question

What is してきた?

文化という言葉は、芸術や学問など人間が生み出した高い達成度を持つもの（ハイカルチャー）を指すとともに、人間の社会が長年にわたって形成してきた慣習や振舞いの体系を指す (source)

I suppose it's a conjugated form of する, but I can't find it.

I don't know if it has anything to do with this answer.

Answer 1

して is the te-form of する, and きた is the past form of くる. Here, くる is one of the Japanese subsidiary verbs that adds a feeling of "over a period of time (up until now)". See:

• Difference between -ていく and -てくる
• What's the difference between 歩んでいった and 歩んできた?

Technically speaking, subsidiary verbs like (-て)いく, (-て)しまう and (-て)みる are not part of verb conjugations. They are different verbs, as the name suggests. The conjugation list you linked does not show every possible combination of a verb and a subsidiary verb because they are not conjugations in the first place. (As an exception, the so-called "-teiru form" is on the list even though いる is a subsidiary verb. This is only for the convenience of beginners whose first language is English.)