As others said, the (unmodified) LCL is fine (TForm, TButton, TLabel, and similar)
With those you can build your app, sell it for millions, and keep all of it (except taxes, but that's not our fault).
Other components you need to check.
- SynEdit for example existed before lazarus, so it has (must have) the license from the original, which is (please check / from memory) MPL/GPL)
- Including code from the IDE (e.g. ide directory): GPL (but its not a packages, so you need to copy the files, unlikely.
- Including code form the debugger(s): GPL
- Code from the designer: ...
- Pascal Script: See readme and REMObject's license
If you look at the project inspector, you see the packages used.
You can open each package (and from there further dependencies of more packages) and check the license.
And yes, it would be nice, if there was an easier way to get an overview....
Anyone wants to contribute?