Questions not answered by https://classic.yarnpkg.com/en/docs/yarnrc

[rulatir]

The config command may also be used to set these options. Yarn will merge .yarnrc files up the file tree.

1. It will merge .yarnrc files up the file tree starting from where?
2. If there are several .yarnrc files "up the file tree", and I make a configuration change using yarn config set <key> <value>, which .yarnrc file will store it?
3. Where is yarn config -g configuration stored?
4. Can I specify where I want yarn to read and write yarn config -g configuration from/to, or am I limited to built-in configuration-finding logic?
5. Is there an editable (i.e. other than built-in defaults) configuration store the location of which depends only on where yarn is installed, and not on where it is invoked? In other words, is there a way to "configure this yarn" rather than "configure this project"?