Chrome Experience is an open source browser, with all Google Chrome goodies. To check out the source code locally, don't use git clone! Instead, follow the instructions on how to get the code.
Documentation in the source is rooted in docs/README.md.
Learn how to Get Around the Chromium Source Code Directory Structure .
For historical reasons, there are some small top level directories. Now the guidance is that new top level directories are for product (e.g. Chrome, Android WebView, Ash). Even if these products have multiple executables, the code should be in subdirectories of the product.
If you found a bug, please file it at https://crbug.com/new.