@SpeakYourMind Curious about this, so I checked the site, and based on the weird stuff I saw, it appears maybe the site is misconfigured by a "cookieless advertising solution" service. I can't know for sure, but that's what it looks like based on the certificate they use for the secure version of that site.
Honestly, I wouldn't worry about it. Maybe just clear your Vanadium history and cache and all that then see if it pops up again. Vanadium is sandboxed, as are all sites it opens.
If you're in the owner profile, you'll see apps installed in other profiles (assuming you're logged in as owner so that's why you see Google Play there). Also, when looking at apps installed on your phone, don't worry about system apps assuming you haven't done something unsupported like rooting your phone.
SpeakYourMind Android Open Source Music Player
I don't know why this is there, but it's on my phone too as a system app. Probably has to be there for some reason.
SpeakYourMind Calendar
I've read GrapheneOS devs say that the calendar app launcher was removed but the app itself has to remain to handle certain system intents.
SpeakYourMind Wireless emergency alerts
part of AOSP - you can disable the alerts if you want.