Is it a bug that minus sign $2212 (a key component of $B1 Plus Minus and $F7 Divided By) uses the Plus sign ($2B) as its source, not Hyphen-Minus ($2D)?
Because it certainly bugs me!
For anyone looking for the fix, on Line 21929 of CompositeData.xml, change 43 to 45.
No. It’s not a bug. The hyphen glyph may not be either horizontal or symmetrical and it is usually a different width to the plus sign.
The minus and plus signs are often the same width as the digits in fonts with lining figures. If the minus sign is generated from the plus sign, it ensures that the horizontal strokes align, and are of the same weight. The same goes for the ± sign, which is generated from plus and minus, not from plus and hyphen.
Top Row: Digit Zero
Middle: Plus, Logical Not, Plus Minus, Divides, Minus
Bottom: Hyphen $1D
I would not recommend this. The definition for Plus Minus also includes a line for getting the glyph metrics from glyph 43 (plus), so the width of the Plus Minus glyph will then change to match the advance width of the hyphen glyph (45).
Keep reporting bugs if you think that you found them. I am just an amateur, and there are sure to be things that could be improved. The time required doesn’t justify a lot of changes though, as users with specialist needs can and should edit the data files to suit themselves.