Hi, I'm working on a PR for Solidus that also involves changes in the Starter-Template. To test this, I'm installing the starter, but it installs the latest stable version and not the latest master of the template. What's the best prepare the changes on the current master?

If you are on Solidus master, it should use the latest from the starter frontend: https://github.com/solidusio/solidus/blob/master/core/lib/generators/solidus/install/app_templates/frontend/starter.rb#L3

oh so, if I point the Rails project Gemfile to solidus-core master branch, it'll pull the master of the template?

yes, but before installing the starter, like with

rails new my_store
bundle add solidus --github 'solidusio/solidus'
bin/rails generate solidus:install

ok, thank you, I will try

thanks to you for contributing!