Drupal Hook & Theme Hook
Drupal official “File“ module overview, how to add file field to a content type, managing its location and access, how to access private files, and how to delete files.
https://www.drupal.org/docs/8/core/modules/file/overview
The difference between public and private folder in drupal file system, and overriding the behavior of the private files via hook_file_download() to allow guest user to download the private files based on conditions.
Drupal 10 theme system overview, the twig engine, the theme hooks, the preprocessing for template files (THEME_preprocess_HOOKsuch as olivero_preprocess_page)
https://api.drupal.org/api/drupal/core!lib!Drupal!Core!Render!theme.api.php/group/themeable/10
what hooks can i override in custom theme’s “themename.theme” file for drupal
https://www.perplexity.ai/search/what-hooks-can-i-override-in-c-gSsfDy.qSiaR20Q_LYYsww
Unofficial post by drupal at your Fingertips, what is drupal hooks and how to use them ? the complete guide !
https://www.drupalatyourfingertips.com/hooks
https://www.drupalatyourfingertips.com/hooks#hook-preprocess
List of all hooks avaiable in the Drupal API
https://api.drupal.org/api/drupal/core!core.api.php/group/hooks/
https://api.drupal.org/api/drupal/core!core.api.php/group/hooks/10