There is quite a bit of documentation of DelphiDabbler software.
Each supported application has its own documentation. See the app's own page on this site for details. A couple of mothballed applications still have documentation available too.
Every currently supported code library project also has its own documentation, detailed on it's own page. There is also comprehensive documentation of each project's units, classes, methods etc. available from https://lib-docs.delphidabbler.com/.
There are numerous FAQs:
Finally, there are a small number of Delphi notes on this site that have been assembled over the years.