Is there any documentation to help understand qgs file in QGIS?

Hello. I’m new in QGIS and any Geographic domain.

I use QGIS to make my own map by importing too many raster&vector files.

I’m going to deploy my map made from qgis by using my other web app.

I know that qgs file contains entire configuration like order, filter, styles of each layer.

I want to parse this qgs file, so is there any documentation to understand and make use of qgs file?

Thank you for all reply in advance.