Not sure why dwbit's comment got killed, they furthered the conversation and sourced information well by, inter alia, linking to "What third-party services, libraries or identifiers are used in my Bitwarden account?" on Bitwarden's FAQ (https://bitwarden.com/help/security-faqs/#q-what-third-party...).
"For those who prefer to exclude all 3rd party communication, Firebase and Microsoft Visual Studio App Center are removed completely from the F-Droid build. Additionally, Turning off push notifications on a self-hosted Bitwarden server will disable using the push relay server."
