That seems familiar - perhaps it's a unicode character identifier. Still, the drawing is broken and needs to be fixed. I'm supposing this because "U+" is used as a unicode introducer, but something seems to be left out.
Perhaps the software is displaying Unicode values as a fallback because the font does not contain the necessary glyphs. I'd expect the diameter symbol to be the first character in those three tolerance value blocks, but that would be U+2300. The empty set symbol looks similar though, and it is U+2205, so perhaps it was used instead. The rest of the code, and presumably the actual tolerance values, would just be cut off due to the size of the space.
