WordPress File wp-includes/author-template.php

the_author_meta()

Outputs the field from the user’s DB object. Defaults to current post’s author.

the_modified_author()

Displays the name of the author who last edited the current post, if the author’s ID is available.

is_multi_author

Filters whether the site has more than one author with published posts.

the_author

Filters the display name of the current post’s author.