Patches are the files that contain a list of differences between one set of files, and another. You can make changes like addition, deletion in codes through patches. Patches can also be used to make changes to another copy of the original or main file.

In Drupal, patches refer to files containing the differences between the original source code of a module, theme, or core, and a modified version of that code. These modifications are typically made to fix bugs, add new features, or improve the performance of the Drupal site. Patches are often used to contribute changes back to the community or to apply customizations to Drupal installations without directly modifying the core or contributed modules.

When someone creates a patch, they generate it using version control systems like Git. These patches can then be shared, reviewed, and applied by others. Patches play a crucial role in the Drupal community’s collaborative development process, enabling developers to share improvements and fixes in a standardized format. They are often submitted and reviewed on the Drupal.org issue queue as part of the contribution process.