Part of macOS
com.apple.Safari…Safari helper
○ Leave it
Supports Safari, even when Safari isn’t open.
What it is
Handles Safe Browsing checks, bookmarks sync and other Safari services.
If you stop it
macOS starts it again straight away. Leave it.
The verdict
○ Leave it. Part of macOS, or something that starts again by itself. You never need to close these.
In Activity Monitor
com.apple.Safari…SafariBookmarksSyncAgent…SafariLaunchAgent…
… means any name that starts this way.
From Procession’s guide, in the words the app shows.