Description:
For diagnostic purposes, it is very useful to know the exact minor version of the LibreOffice used to produce the PDF. This can be added to the "PDF Producer" metadata.

This metadata can be shown in almost any PDF viewer.

For example, instead of:
LibreOffice 7.5

It should be something like:
LibreOffice 7.5.3.2 (X86_64) / LibreOffice Community

For development versions, it would be something like:
LibreOfficeDev 24.2.0.0.alpha0+ (X86_64) / LibreOffice Community

It would be good to even have the localized version of this text.

Code pointers:
If you look into filter/source/pdf/pdfexport.cxx, you will see that in PDFExport::Export(), aContext.DocumentInfo.Creator is set. You can change it to a new text, and see it in action, by setting:

aContext.DocumentInfo.Creator = "Hello world!";

And then exporting a file to PDF, looking into the metadata.

On the other hand, if you go to Help > About, you will see the same string is visible in the "About" dialog. If you look at cui/source/dialogs/about.cxx, you will see GetVersionString(), which provides the above (localized) string.

Combining these two, one can implement this feature.