Use have_packs+ file directly with grep
Minicleanup in do_push
Introduce filter_to, pick_fields
Update Branchlist using filter_remove
Fix checking for multiple keys
Use filter_to for key_line
Replace wc -l with line_count
Use filter_to for pruning Packlist after repack
Code and naming conventions around return variables
Edit wording in README
Unify filter_to and its negation, also make it faster by direct append
Rename main manifest globals for consistency and symmetry
Cleanup use of "quotes"
Fixup cleanup at exit
Use $1, $2 instead of $@ here

If found a bug in mksh, where it would not split "$@" if IFS is null
(reported).
More specific pattern for manifest filter
Refactor fetch and repack
use gpg_hash
remove splitcolon use