Electronics 2000

Question for anyone familiar with PCB design and Gerber file format.
I have been reading this document but unfortunately it contains too much engineering gibberish and not enough simple explanation

X-2794000Y-254000D2*
D14*
Y-508000D1*
X-2286000Y-762000D2*
X-2540000D1*
X-2794000D1*

It seems obvious the the X and Y denote the x and/or y coordinates of a point in a polyline.
And the D1 and D2 denote move to and llne to commands

But hat are the units here? Are those integers referring to steps (as in a stepper motor) or millimeters or something else?
But I can't figure out what all of this means.

%TF.GenerationSoftware,Novarm,DipTrace,3.2.0.1*% // This is just the software that generated the gerber file
%TF.CreationDate,2018-11-07T12:25:27+09:00*% // And the file date....all good
%FSLAX35Y35*% // What is this?
%MOMM*% // What is this?
%TF.FileFunction,Copper,L2,Bot*% // Copper clad board but what do L2 and Bot mean?
%TF.Part,Single*% // Single sided PCB....all good
%TA.AperFunction,Conductor*% //
%ADD14C,2.0*% // What do these two lines mean?
%TA.AperFunction,ComponentPad*% // Get this....all good
%ADD15C,2.3*% // My pads in diptrace were circles of 2.3mm diameter.....all good

Sorry I have not had any experience with this, but I think that you will be able to find most - if not all - of the information you need by googling "gerber file". The net is usually the first place to try.