WordPress 5.5.3-alpha fixes issue introduced in 5.2 which makes it impossible to install WordPress on a brand new website without a database connection. The default Twenty themes installed as part of the pre-release package were not activated and therefore remain non-functional unless you installed them previously. The Akismets default Twenty themes were also not activated. These themes and plugins are safe to delete these features should you prefer not to use them.”]
Source: https://wordpress.org/news/2020/10/wordpress-5-5-3-maintenance-release/