This feature is only available to users who can directly see the pma_bookmark table. This is the default name given when the linked-tables infrastructure is installed. In a multi-user installation, this table is usually located in a database invisible to unprivileged users. Browsing this table displays a new Execute bookmarked query button, which triggers the execution of the query:

Seeing the text of the query while browsing this table is possible if $cfg['ShowBlob'] is set to TRUE. Alternatively, we could click the pencil icon to open the Edit page for a specific row, so that we can see the query's complete text.