If I tell gpg to create a notation name that is too long, gpg hits a BUG().
Edit: This can be reproduced as follows:
```
# create a keypair as usual, details don’t matter
long_str=$(python3 -c '"a" * 100000')
gpg2 --sign -N "a@b.invalid=$long_str" -o /dev/null /dev/null
```