The ChromeCall sample application uses a Manifest V2 format and Google only accepts Manifest V3 format extensions after Jan. 17, 2022: developer.chrome.com/docs/extensions/mv2/runtime_host_permissions/ (timeline is at developer.chrome.com/docs/extensions/mv3/mv2-sunset/ and in January 2023, Chrome itself won't run any Manifest V2 extensions, so all current ones need to be updated as well).
The Manifest V3 Migration Checklist is here: developer.chrome.com/docs/extensions/mv3/mv3-migration-checklist/
Additionally, Google requires justification in the App Store when publishing an app for each type of permission (each of the "permissions" options from the manifest), which require a sub-1000-character description for why the permission is required. Some are more obvious than others, but a succinct description of why each permission is necessary would be helpful to embed in the readme for reference. The main one I can't explain is "notifications" as I'm not sure what notifications the extension needs to provide that are not user-initiated, since it's not receiving inbound calls.
Additionally, the Web Store says that the Host Permission requirements (*/* and */*) mean the extension may require an in-depth review which will delay publishing. I don't know if there's a way to not require this (I suspect not), but if so, it would be nice to have it refactored. The above are more important, however.
Google is going to stop accepting updates to Manifest V2 extensions entirely in 2023, but already stopped accepting newly published extensions.
A new version (v1.0), to comply with the new Chrome store guidelines, has been published and is now available via the Chrome Web Store at the following link: