Describe Ad-hoc signing on MacOS (#3289)

Author: matthewCmatt

src/content/docs/distribute/Sign/macos.mdx

@@ -52,7 +52,7 @@ With the certificate installed in your Mac computer keychain, you can configure
 
 The name of the certificate's keychain entry represents the `signing identity`, which can also be found by executing:
 
-```
+```sh
 security find-identity -v -p codesigning
 ```
 
@@ -79,7 +79,7 @@ and configure the `APPLE_CERTIFICATE` and `APPLE_CERTIFICATE_PASSWORD` environme
 3. Select the path to save the certificate's `.p12` file and define a password for the exported certificate.
 4. Convert the `.p12` file to base64 running the following script on the terminal:
 
-```
+```sh
 openssl base64 -in /path/to/certificate.p12 -out certificate-base64.txt
 ```
 
@@ -182,3 +182,22 @@ Notarization is required when using a _Developer ID Application_ certificate.
 [creating a certificate signing request]: https://developer.apple.com/help/account/create-certificates/create-a-certificate-signing-request
 [Certificates, IDs & Profiles page]: https://developer.apple.com/account/resources/certificates/list
 [app-specific password]: https://support.apple.com/en-ca/HT204397
+
+## Ad-Hoc Signing
+
+If you do not wish to provide an Apple-authenticated identity, but still wish to sign your application, you can configure an _ad-hoc_ signature.
+
+This is useful on ARM (Apple Silicon) devices, where code-signing is required for all apps from the Internet.
+
+:::caution
+Ad-hoc code signing does not prevent MacOS from requiring users to
+[whitelist the installation in their Privacy & Security settings](https://support.apple.com/guide/mac-help/open-a-mac-app-from-an-unknown-developer-mh40616/mac).
+:::
+
+To configure an ad-hoc signature, provide the pseudo-identity `-` to Tauri, e.g.
+
+```json
+"signingIdentity": "-"
+```
+
+For details on configuring Tauri's signing identity, see [above](#configuring-tauri).