Don't take into account the INVISIBLE flag for well-known annotations

src/core/annotation.js

@@ -838,6 +838,17 @@ class Annotation {
    */
   setFlags(flags) {
     this.flags = Number.isInteger(flags) && flags > 0 ? flags : 0;
+    if (
+      this.flags & AnnotationFlag.INVISIBLE &&
+      this.constructor.name !== "Annotation"
+    ) {
+      // From the pdf spec v1.7, section 12.5.3 (Annotation Flags):
+      //   If set, do not display the annotation if it does not belong to one of
+      //   the standard annotation types and no annotation handler is available.
+      //
+      // So we can remove the flag in case we have a known annotation type.
+      this.flags ^= AnnotationFlag.INVISIBLE;
+    }
   }
 
   /**
@@ -1817,7 +1828,9 @@ class WidgetAnnotation extends Annotation {
     // since the visibility can be changed by js code, hence in case
     // it's made viewable, we should render it (with visibility set to
     // hidden).
-    return !this._hasFlag(flags, AnnotationFlag.INVISIBLE);
+    // We don't take into account the `INVISIBLE` flag here, since we've a known
+    // annotation type.
+    return true;
   }
 
   /** @inheritdoc */

test/pdfs/issue17169.pdf.link

@@ -0,0 +1 @@
+https://github.com/mozilla/pdf.js/files/13161366/stamp-signature.pdf

test/test_manifest.json

@@ -8181,5 +8181,13 @@
       "lastPage": 2,
       "type": "eq",
       "forms": true
+   },
+   {
+      "id": "issue17169",
+      "file": "pdfs/issue17169.pdf",
+      "md5": "fa57aa9442c5e2d6d9e61bbb8856a55f",
+      "link": true,
+      "rounds": 1,
+      "type": "eq"
    }
 ]

test/unit/annotation_spec.js

@@ -4082,7 +4082,7 @@ describe("annotation", function () {
         const popupDict = new Dict();
         popupDict.set("Type", Name.get("Annot"));
         popupDict.set("Subtype", Name.get("Popup"));
-        popupDict.set("F", 25); // not viewable
+        popupDict.set("F", 56); // not viewable
         popupDict.set("Parent", parentDict);
 
         const popupRef = Ref.get(13, 0);
@@ -4097,7 +4097,7 @@ describe("annotation", function () {
         expect(data.annotationType).toEqual(AnnotationType.POPUP);
         // We should not modify the `annotationFlags` returned through
         // e.g., the API.
-        expect(data.annotationFlags).toEqual(25);
+        expect(data.annotationFlags).toEqual(56);
         // The popup should inherit the `viewable` property of the parent.
         expect(viewable).toEqual(true);
       }