Hi @Matte, welcome to the forum! 
Looking at the original post,
the ‘proposal’ that was linked to specifies the subtitle-generation process shouldn’t be user-configurable to keep things simple. Looking at the code in the pull request, that was indeed the case. To add extra custom information/content you would need to modify the subtitles after they’re generated, which you could presumably do in one of the available Software Packages, or possibly with some simple code if you’re consistently adding the same information.
If you look at the image in the original post, the data types/headings are right-aligned whereas the corresponding values are left-aligned, so that they all line up in the display, and there’s a consistent gap between each data type and its value. The \an3 command would appear to perform that right-aligning.
I don’t know enough about the Advanced SubStation specification to know if it’s possible to combine text with different formatting in the same Dialogue line. If it is possible then I would assume it could be done with something like
Dialogue: 0,0:00:00.9,0:00:01.9,Default,0,0,0,{\an3\pos(950,1075)}Roll:\NPitch:\NHeading:{\pos(960,1075)}-0.7 deg\N4.4 deg\N123 deg
but I have no idea if that’s the correct syntax, or whether all different formatting needs to be kept on its own Dialogue line to function correctly.