load-admin_page_gutenberg-edit-site

See hook in action

See this hook used in plugins:

Select Plugingutenberg.13.8.2gutenberg.13.9.0gutenberg.14.0.2gutenberg.14.0.3gutenberg.14.2.0gutenberg.14.3.1gutenberg.14.4.0gutenberg.14.5.0gutenberg.14.5.3gutenberg.14.6.1gutenberg.14.7.0gutenberg.14.8.4gutenberg.15.1.0gutenberg.15.2.1gutenberg.15.2.2gutenberg.15.2.4gutenberg.15.3.1gutenberg.15.4.0gutenberg.15.6.2gutenberg.15.7.0gutenberg.15.7.1gutenberg.15.8.0gutenberg.15.9.0gutenberg.16.1.0gutenberg.16.2.1gutenberg.16.5.0gutenberg.16.5.1gutenberg.16.6.0gutenberg.16.8.1gutenberg.16.9.0gutenberg.17.0.2gutenberg.17.1.2gutenberg.17.2.3gutenberg.17.3.0gutenberg.17.4.1gutenberg.17.5.0gutenberg.17.5.2gutenberg.17.6.5gutenberg.17.7.0gutenberg.17.8.0gutenberg.17.8.2gutenberg.17.9.0