The idea to use a /doc folder with various notes (in markdown format, github style) was discussed on the mailing list and was generally met with positive response.

Since a number of external web pages exist that link to the release notes in /doc-files, it makes sense to use that folder (no need to create multiple doc folders at the top level). The release notes and everything else at the top level should remain there. A number of subfolders could be created to host various documents intended for openjfx developers, such as build instructions and the link.

We could start by adding the following notes:
- build instructions in build/ subfolder
- pixel snapping in controls/ subfolder
- behavior specific information (such as key maps in behavior/ subfolder, see https://github.com/andy-goryachev-oracle/jfx/pull/4)

and any other topics we consider important.

Edit 2023/09/05: we already have /doc-files, so it probably makes more sense to use that and simply create subdirectories in it.