install_themes_tabs
Filter Hook: Filters the tabs shown on the Add Themes screen.
Source: wp-admin/theme-install.php:151
install_themes_pre_{$tab}
Action Hook: Fires before each of the tabs are rendered on the Install Themes page.
Source: wp-admin/theme-install.php:91
install_themes_{$tab}
Action Hook: Fires at the top of each of the tabs on the Install Themes page.
Source: wp-admin/theme-install.php:257