All reports of unnecessary-source-date-epoch-assignment for the archive. The extended description of this tag is:
There is an assignment to a SOURCE_DATE_EPOCH variable in the debian/rules file.
As of dpkg 1.18.8, this is no longer necessary as dpkg exports this variable if it is not already set. However, you can also include /usr/share/dpkg/pkg-info.mk or /usr/share/dpkg/default.mk to ensure it is exported.
This tag has not been emitted in any package tested by Lintian.