lastBuildDate property
The most recent date when the RSS feed was recreated/regenerated.
Typically, an RSS feed is recreated for the purpose of adding or altering content, in which case lastBuildDate should match pubDate. However, it's possible that the value is recreated for some other purpose, in which case pubDate will be behind lastBuildDate.
Think of the RSS feed file as cached data, and think of lastBuildDate as the date in which the cache was most recently updated.
Implementation
final String? lastBuildDate;