Blog Settings has three tabs: Blog Authors, Categories and Tags. There are no other settings on this page.
Authors
An author is a display profile, not a user account: a name, a URL slug, a bio, an avatar, up to five social links and per-language name and bio. Several can byline a post, in order, and the first shows on cards. The profile is not linked to an admin user from this screen. Each post's creator (an admin user) is separate and gets the review notifications.
An author cannot be deleted while it is on any post, including drafts and Trash, even though the dialog reads as if it would just be unlinked. Reassign the posts first. A privacy erasure anonymises a profile instead of deleting it. The public author page shows 12 posts and no pager.
Categories
Hierarchical: a category can have a parent, and cannot become its own ancestor. Fields: name, slug, parent, description, translations. Slugs are unique per kind (a tag and a category can share one).
Uncategorized is created automatically when a published post would have no category. It is marked System: its slug and parent are locked, it cannot be deleted, and it is hidden from the public (no archive page). Deleting another category moves published posts that had only that category into Uncategorized, makes its child categories top level and removes the archive page.
Tags
Flat, no parents and no Uncategorized fallback. Deleting a tag just removes it from posts.
Editing translations
Take care when editing a category or tag in a multilingual site: the form now starts from the saved translations, so open it and check the language tabs before saving.
Archives
Category, tag and author archive pages show only the first 12 posts and have no pager.
Permissions
cms.read to view; cms.taxonomy.manage for categories and tags; cms.authors.manage for authors.