What is the meaning of ANxxx and ACxxx in the comments of MS-DOS 4.0 source code

[bugthis]

The assembly source code of MS-DOS 4.0 contains a number of identifiers as comments that begin with AN or AC and are followed by a three-digit number.

Example from KEYBCMD.ASM

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PUBLIC LANG_PTR_SIZE        ;AN000;
PUBLIC CP_PTR_SIZE        ;AN000;
PUBLIC NUM_ID        ;AN000;
https://github.com/microsoft/MS-DOS/tree/main/v4.0/src

Is this a reference to internal documentation that only Microsoft has or are these the authors' initials? AN could stand for annotation, AC for assembly code perhaps?
If this is part of documentation, where can I find it? In any case, it wasn't included with the release of the source code as open source. I searched the github repository for MS-DOS but didn't find anything like that.

[NoCforMe]

Dunno; did you see this in one of those files?

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;      AN000  version 4.00  Jan. 1988
Maybe it's just refers to a certain revision?

[greenozon]

The identifiers ANxxx and ACxxx in the comments of MS-DOS 4.0 source code are not officially documented,
and their exact meaning remains unclear.
 Some speculate that AN could stand for "annotation" and
AC for "assembly code," possibly referencing internal documentation or conventions used by the developers

[bugthis]

Dunno; did you see this in one of those files?

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;      AN000  version 4.00  Jan. 1988
Maybe it's just refers to a certain revision?

Yes, I saw that. I assume that refers to the MS-DOS version, which in this case would be 4.0. This also comes up frequently in the comments in the code.

[bugthis]

The identifiers ANxxx and ACxxx in the comments of MS-DOS 4.0 source code are not officially documented,
and their exact meaning remains unclear.

That's what it looks like.

Some speculate that AN could stand for "annotation" and
AC for "assembly code,"

Yup, that's me. Did AI told you that?

possibly referencing internal documentation or conventions used by the developers

That would be my assumption. One can only hope that those who persuaded Microsoft to release the MS-DOS 4.0 code will ask again about this. Maybe Microsoft could publish the documentation, if there is one.