the program that starts Minecraft. Can also be used to change skins, view release notes and more. Please also use [minecraft-java-edition] on questions with this tag.
The Minecraft launcher is an operating system specific (but always visually and functionally similar) program that is usually just used to start Minecraft. It can however also be used to upload or switch skins, view changelogs for releases and snapshots and other Minecraft blog posts.
In the easiest setup, the launcher handles downloading and installing Java, downloading the game and its assets and preparing the Minecraft data folder automatically. But it also has many options, like starting any of almost all past Minecraft versions and even modded Minecraft relatively easily, playing with different accounts, using different game directories, changing the starting resolution and applying custom Java arguments (like maximum RAM usage) and executable. The game's log file can also be opened in a separate window that allows filtering and automatically updates whenever the log changes.
There are also a community-made custom launchers.
Please also use minecraft-java-edition on questions with this tag.
The launcher (usually) shows a popup when Minecraft crashes, but usually those crashes are not actually related to the launcher and therefore these questions should not be tagged with minecraft-launcher.
