noun
generic content portion
Computing term for a part of a document or data structure that contains content independent of specific formatting or presentation.
このテンプレートでは、共通内容部に本文を記述します。
In this template, you write the main text in the generic content portion.
Compound of 共通 (common) + 内容 (content) + 部 (part). The exact derivation is uncertain; it appears to be a technical term formed within computing contexts.