Transform ids into readable names
Inkscape stores labels in a inkscape:label attribute. Use it when available.
Illustrator converts layer/group names as ids, with apparently the following rules:
- use a 50-digit suffix to uniquify ids (in case of conflicting labels)
- escape non-alphabetic characters as _xNN (with NN being the ASCII code)
- replace _ with whitespace. ids could be converted back to readable labels using these rules.