The "d" is used here so that you can type it, just like "us" for "µs" (microseconds).

There is other issue, if you change "Unit" > "Rotation" to "Radians", you will not see "r",
and what's more, you will not be able to input in degrees (with "d") or in arcminutes/arcseconds.

In D8369#203805, @Yevgeny Makarov (jenkm) wrote:

The "d" is used here so that you can type it, just like "us" for "µs" (microseconds).

There is other issue, if you change "Unit" > "Rotation" to "Radians", you will not see "r",
and what's more, you will not be able to input in degrees (with "d") or in arcminutes/arcseconds.

Thank you for your remarks.

Not sure if this is just a workflow thing, but when I put any value on the Location field I never write the units

I tried my patch and I still can input arcminutes/arcseconds and even "r" after the number and Blender does the conversion , just type the value you want and then the unit text.

If you are in radians and you write a value plus de "d" it will not convert it (tested on the official 2.83.3). So that's a problem in the Blender unit conversion which I'm not touching here.

Maybe I'm didn't understand your comments but for what I can see, my patch doesn't affects the usability.

I mean, this d is used for typing, to indicate units,
since you can't type ° from the keyboard.
If you are in Radians, you should be able to enter d for Degrees.
The current conversion issue is not caused by your patch.

See typedef struct bUnitDef.

/** this is used for display*/
const char *name_short;
/** keyboard-friendly ASCII-only version of name_short, can be NULL */
const char *name_alt;
/* if name_short has non-ASCII chars, name_alt should be present */

I mean, this d is used for typing, to indicate units,
since you can't type ° from the keyboard.
If you are in Radians, you should be able to enter d for Degrees.

@Juan (jc4d) , Thanks for the patch but applying this changes will lead to other problems (as mentioned by jenkm)

(Adding user interface as a tag here so they can decide to close the patch or not) :)