Lintian tag information: default-mta-dependency-not-listed-first (type: warning)

Description (from lintian-explain-tags)

This package has a relationship with the mail-transport-agent or
default-mta packages but does not specify the default-mta as an first
option.

default-mta and mail-transport-agent should only ever be in a set of
alternatives together, with default-mta listed in the primary position.

Please rearrange the dependencies such that default-mta is listed first.

Visibility: warning
Show-Always: no
Check: fields/package-relations

Show affected packages