See here: https://meta.stackexchange.com/q/105117/168681 for problem description.
Having done dung-beetle work of manual retagging about 150 "mdb" questions (took me about 5 months), I hereby announce the "mdb" tag as extinct and I'm asking to lock it permanently, due to ambiguity of the acronym.
The tag was used in the meaning of:
- message driven bean (about 70%),
- MS Access database (about 30%),
- a Unix debugger (twice).