Pull Request
When working together on a project, pull requests are a great way to manage ideas for implementations developers have and merge them with the main working branch.
At their core, pull requests are a collection of patches which can be applied to a codebase, usually grouped in a git branch, represented by the commits from the point when the branch branched off. Most online repository platforms like github, gitlab or gitea allow commenting on these patches, including discussions on the changes and requesting changes before they are merged. This allows the developers to have an easy way to review changes before merging everything together.