The tag is present in Lintian version 2.109.6. That is the most recent version we know about.
The package has a very long filename. This may complicate shipping the package on some media that put restrictions on the length of the filenames (such as CDs).
For architecture dependent packages, the tag is emitted based on the length of the longest architecture name rather than the name of the current architecture.
This length will be written in brackets after the actual length.
Please refer to https://lists.debian.org/debian-devel/2011/03/msg00943.html for details.