There is quite a bit of documentation of DelphiDabbler software.
Each application has its own documentation. See the app's own page on this site for details.
Every code libray sub-project also has its own documentation that is listed on it's page. The is also comprehensive documentation of the sub-project's units, classes, methods etc. available the delphidabbler/ddab-lib-docs GitHub repository. For some projects, anyway - others are on the todo list!
There are numerous FAQs:
Finally, there are a small number of Delphi notes on this site that have been assembled oer the years.