You probably have a package in your install list that requires the dll.
That is, if you ever installed a package that requires it, then that will be noted in your config.
Until you actually go to menu Packages > Packages, and uninstall it, this package stays in the list of installed packages.
- If you uninstall Lazarus, the config remains on your PC
- If you install a new Lazarus, the config remains on your PC
Though in the installer there is a checkbox to clean the config, so you can get rid of it.
After installing a new Lazarus, the installed package is pending. It is not compiled into you lazarus exe.
But as soon as you recompile the IDE for any reason (install any other package) the pending packages are being installed too.