What does the breakpoint indicator do?
The breakpoint indicator shows you which breakpoint you're viewing your website at in the bottom left of the browser.
The Site Studio breakpoint indicator is a module that is included within Site Studio. When enabled, this adds an icon to the lower left of the browser window which indicates the current breakpoint your browser is sized to. This is a useful tool when building websites as you can quickly see what your layout is doing at each breakpoint.
The breakpoint indicator can be made visible to specific roles by enabling the Drupal permission. The module can be uninstalled on production websites as its a tool for site-building.