Add digital-credential-get experimental permission to features.md (#549)

* Add digital-credential-get experimental permission to features.md

Co-authored-by: Sam Goto <[email protected]>

features.md

@@ -85,6 +85,7 @@ experimentation by web developers.
 | `browsing-topics` | [Explainer](https://github.com/jkarlin/topics/) | Status "[Started](https://bugs.chromium.org/p/chromium/issues/detail?id=1294456)" in Chrome |
 | `captured-surface-control` | [Captured Surface Control API][capture-surface-control]  | In [Origin Trial](https://chromestatus.com/feature/5092615678066688) |
 | `conversion-measurement ` | [Explainer](https://github.com/WICG/conversion-measurement-api#publisher-controls-for-impression-declaration) | Experimental in Chrome<sup>[3](#fn3)</sup> |
+| `digital-credentials-get` | [Explainer](https://wicg.github.io/digital-credentials/) | Behind a flag in Chrome<sup>[6](#fn6)</sup>
 | `focus-without-user-activation` | [focus-without-user-activation.md](policies/focus-without-user-activation.md) | Status "[Open](https://bugs.chromium.org/p/chromium/issues/detail?id=965495)" in Chrome |
 | `join-ad-interest-group` | [Protected Audience (formerly FLEDGE)][protected-audience] | Behind a flag in Chrome<sup>[4](#fn4)</sup> |
 | `local-fonts` | [Local Font Access API][local-fonts] and [Explainer](https://github.com/WICG/local-font-access/blob/main/README.md) | [Experimental in Chrome](https://chromestatus.com/feature/6234451761692672) |
@@ -121,6 +122,9 @@ and/or implementations have been removed.
 <a name="fn5">[5]</a>: Implemented in [Chrome 100](https://chromestatus.com/feature/5252960583942144) as `window-placement`;
 changed in [Chrome 111](https://chromestatus.com/feature/5146352391028736) to `window-management`.
 
+<a name="fn6">[6]</a>: To enable this, user the Chrome command line flag
+`--enable-features=WebIdentityDigitalCredentials`.
+
 [attribution-reporting]: https://wicg.github.io/attribution-reporting-api/#permission-policy-integration
 [battery-status]: https://w3c.github.io/battery/#permissions-policy-integration
 [bluetooth]: https://webbluetoothcg.github.io/web-bluetooth/#permissions-policy