small improvements

* Added more references to the FAQ
* Added reference to the XDA post about Gravatars

tutorials/settings-overview.md

@@ -134,7 +134,7 @@ There are multiple ways to show an avatar for each sender. You can enable multip
 3. Enable the options of your choice
 
 **NOTE:** Apart from the generated icons, there might be a privacy risk with each available option.
-Gravatars and Libravatar might not be available in the PlayStore version as Google falsely flags the app to be a spyware otherwise.
+Gravatars and Libravatar might not be available in the PlayStore version as Google falsely flags the app to be a spyware otherwise. ALso see [this XDA thread](https://forum.xda-developers.com/t/app-5-0-fairemail-fully-featured-open-source-privacy-oriented-email-app.3824168/page-1125#post-87018167) on the matter.
 
 ## 9. Enable Biometric Authentication
 You might want to protect your app via a PIN or a fingerprint to ensure no unauthorized person gains access to your messages.
@@ -144,6 +144,8 @@ To do so, follow these steps:
 2. Press on the "PIN" or "Enable fingerprint" button
 3. Follow the instruction on your screen
 
+More information can be found in [FAQ #113 How does biometric authentication work?](https://github.com/M66B/FairEmail/blob/master/docs/FAQ-en-rGB.md#user-content-faq113).
+
 ## 10. Enable Error Reporting
 Error reporting is disabled by default However, enabling this helps the developer finding any bugs and improving the app.
 If you want to enable error reporting, do as follows: