I have Call Recorder installed and it is recording phone calls, which I can see in the application. I would like to see these files in filesystem too. Where are they?
I see location Internal storage/CallRecordings, but it contains only few very old recordings, no any new ones.
tl:dr;
Recordings are stored in /data/user/0/com.appstar.callrecorder/files
Your device needs to be rooted and by using a root file explorer you can see. If your device is not rooted, you can't see them.
Caveats
I downloaded the free version of app to test and since both free and paid version of app have the same version number and updated on the same day, this answer should hold good.
Paid version does not make mention of compatibility with Android 11 (w.r.t storage), so one more reason to assume that this answer is valid.
I am currently on Android 12 but this answer should hold good for Android 11 since AFAIK there have been no changes in storage policy between Android 11 & Android 12.
Caveats out of the way :
App targets Android 10 (SDK 29) which you can verify by checking app manifest using an app from Play Store.
It has not been updated to target Android 11, which your device is running.
Android 11 introduced major changes in storage ( see Storage updates in Android 11). Without getting into technical details, what this means is that Android 11 (and upwards) give you better privacy by shielding app data (scoped storage). App data is only available to the app using it (file explorers also cannot see it without root privileges).
App developers can choose to temporarily opt-out of scoped storage by setting a manifest attribute as android:requestLegacyExternalStorage="true. App manifest does not show this attribute, hence Android 11 scoped storage restrictions apply (you can ask the developer reasons) and therefore, you can't see where they are stored (without root). Likely reason why you can see only some old recordings is that these were saved in default location in Android 10 and you subsequently upgraded to Android 11.
So, if you want to see the files you can share →save/copy to desired folder location with a file explorer that does this (as also mentioned in Shenk's answer, some file explorer apps do this, I prefer MiXplorer).
Also see
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