Abandoned packages and Parse error | PHP 8.0.11

[andriilive]

Package brain/amygdala is abandoned, you should avoid using it. No replacement was suggested. Package brain/brain is abandoned, you should avoid using it. No replacement was suggested. Package brain/striatum is abandoned, you should avoid using it. No replacement was suggested. Package brain/support is abandoned, you should avoid using it. No replacement was suggested. Package twig/cache-extension is abandoned, you should avoid using it. Use twig/cache-extra instead.

( ! ) Parse error: syntax error, unexpected token "\" in /Users/andy/Documents/associationweb/web/app/themes/asweb/vendor/brain/support/src/Facade.php on line 34

[gmazzap]

You're using "master" branch which is long abandoned.

You should use refactoring-fastroute branch (which is the default), or even better one of the releases.