feed_info.txt is a handful of lines: who publishes the feed, its language, which version it is, the dates it is good for, and where to write when it is wrong. Without it, a consumer holding a feed cannot tell whether it has the latest one, how long it is valid, or whom to call. A tiny feed can get away with that. A big one, carried by apps and trip planners across a region, cannot.
The law
The zip has no feed_info.txt (or an empty one), and its files add up to more than 10 MB uncompressed.
How to get pardoned
Add feed_info.txt with at least feed_publisher_name, feed_publisher_url,
feed_lang, feed_version and feed_contact_email. feed_start_date and
feed_end_date are a kindness too.