What kind of entries Feedjira has?

I started to use feedjira. I'm getting entries from url:

feed = Feedjira::Feed.fetch_and_parse(self.url)

puts "Fetching from #{self.url}"

feed.entries.each do |entry|
  unless Feed.exists? guid: entry.id
    newFeed = Feed.create(name: entry.title,
                          summary: entry.summary,
                          url: entry.url,
                          published_at: entry.published,
                          guid: entry.id)

    self.feeds << newFeed
  end
end

I found these entries from tutorials. I haven't found entries from documentation. Are there any other entries that I can get from url like categories?