Unclear What the extra step does to plugin setup is not known.
Claude Code can run headless, which means without its interactive screen, for example when it is started from a script. In that mode it can still install plugins, which are add-ons that extend what Claude Code can do. Plugins come from marketplaces, which are catalogs that list plugins available to install.
When no marketplaces are declared, headless plugin setup used to write a log message and stop there. It now also waits for an extra step to finish before moving on.
The extra step may change which plugins are set up, or how they are set up, when Claude Code runs headless with no marketplaces declared.
What the extra step does to plugin setup is not known.