diff --git a/src/core/obj.js b/src/core/obj.js
index 9aeb8f4a5..342313117 100644
--- a/src/core/obj.js
+++ b/src/core/obj.js
@@ -153,6 +153,47 @@ class Catalog {
     return shadow(this, "metadata", metadata);
   }
 
+  get markInfo() {
+    let markInfo = null;
+    try {
+      markInfo = this._readMarkInfo();
+    } catch (ex) {
+      if (ex instanceof MissingDataException) {
+        throw ex;
+      }
+      warn("Unable to read mark info.");
+    }
+    return shadow(this, "markInfo", markInfo);
+  }
+
+  /**
+   * @private
+   */
+  _readMarkInfo() {
+    const obj = this._catDict.get("MarkInfo");
+    if (!isDict(obj)) {
+      return null;
+    }
+
+    const markInfo = Object.assign(Object.create(null), {
+      Marked: false,
+      UserProperties: false,
+      Suspects: false,
+    });
+    for (const key in markInfo) {
+      if (!obj.has(key)) {
+        continue;
+      }
+      const value = obj.get(key);
+      if (!isBool(value)) {
+        continue;
+      }
+      markInfo[key] = value;
+    }
+
+    return markInfo;
+  }
+
   get toplevelPagesDict() {
     const pagesObj = this._catDict.get("Pages");
     if (!isDict(pagesObj)) {
diff --git a/src/core/worker.js b/src/core/worker.js
index eae578ad6..7dee0f195 100644
--- a/src/core/worker.js
+++ b/src/core/worker.js
@@ -499,6 +499,10 @@ class WorkerMessageHandler {
       ]);
     });
 
+    handler.on("GetMarkInfo", function wphSetupGetMarkInfo(data) {
+      return pdfManager.ensureCatalog("markInfo");
+    });
+
     handler.on("GetData", function wphSetupGetData(data) {
       pdfManager.requestLoadedStream();
       return pdfManager.onLoadedStream().then(function (stream) {
diff --git a/src/display/api.js b/src/display/api.js
index ff7a6aaa3..a44ae82d1 100644
--- a/src/display/api.js
+++ b/src/display/api.js
@@ -805,6 +805,23 @@ class PDFDocumentProxy {
     return this._transport.getMetadata();
   }
 
+  /**
+   * @typedef {Object} MarkInfo
+   * Properties correspond to Table 321 of the PDF 32000-1:2008 spec.
+   * @property {boolean} Marked
+   * @property {boolean} UserProperties
+   * @property {boolean} Suspects
+   */
+
+  /**
+   * @returns {Promise<MarkInfo | null>} A promise that is resolved with
+   *   a {MarkInfo} object that contains the MarkInfo flags for the PDF
+   *   document, or `null` when no MarkInfo values are present in the PDF file.
+   */
+  getMarkInfo() {
+    return this._transport.getMarkInfo();
+  }
+
   /**
    * @returns {Promise<TypedArray>} A promise that is resolved with a
    *   {TypedArray} that has the raw data from the PDF.
@@ -2639,6 +2656,10 @@ class WorkerTransport {
       });
   }
 
+  getMarkInfo() {
+    return this.messageHandler.sendWithPromise("GetMarkInfo", null);
+  }
+
   getStats() {
     return this.messageHandler.sendWithPromise("GetStats", null);
   }
diff --git a/test/unit/api_spec.js b/test/unit/api_spec.js
index a980d5d6b..6fcc068a8 100644
--- a/test/unit/api_spec.js
+++ b/test/unit/api_spec.js
@@ -1209,6 +1209,24 @@ describe("api", function () {
         .catch(done.fail);
     });
 
+    it("gets markInfo", function (done) {
+      const loadingTask = getDocument(
+        buildGetDocumentParams("annotation-line.pdf")
+      );
+
+      loadingTask.promise
+        .then(function (pdfDoc) {
+          return pdfDoc.getMarkInfo();
+        })
+        .then(function (info) {
+          expect(info.Marked).toEqual(true);
+          expect(info.UserProperties).toEqual(false);
+          expect(info.Suspects).toEqual(false);
+          done();
+        })
+        .catch(done.fail);
+    });
+
     it("gets data", function (done) {
       const promise = pdfDocument.getData();
       promise
diff --git a/web/app.js b/web/app.js
index 53a1bff38..a414c4b7c 100644
--- a/web/app.js
+++ b/web/app.js
@@ -247,6 +247,7 @@ const PDFViewerApplication = {
   triggerDelayedFallback: null,
   _saveInProgress: false,
   _wheelUnusedTicks: 0,
+  _idleCallbacks: new Set(),
 
   // Called once when the document is loaded.
   async initialize(appConfig) {
@@ -743,6 +744,10 @@ const PDFViewerApplication = {
     this.contentDispositionFilename = null;
     this.triggerDelayedFallback = null;
     this._saveInProgress = false;
+    for (const callback of this._idleCallbacks) {
+      window.cancelIdleCallback(callback);
+    }
+    this._idleCallbacks.clear();
 
     this.pdfSidebar.reset();
     this.pdfOutlineViewer.reset();
@@ -1334,6 +1339,16 @@ const PDFViewerApplication = {
       pdfViewer.optionalContentConfigPromise.then(optionalContentConfig => {
         this.pdfLayerViewer.render({ optionalContentConfig, pdfDocument });
       });
+      if ("requestIdleCallback" in window) {
+        const callback = window.requestIdleCallback(
+          () => {
+            this._collectTelemetry(pdfDocument);
+            this._idleCallbacks.delete(callback);
+          },
+          { timeout: 1000 }
+        );
+        this._idleCallbacks.add(callback);
+      }
     });
 
     this._initializePageLabels(pdfDocument);
@@ -1398,6 +1413,23 @@ const PDFViewerApplication = {
     scripting.createSandbox({ objects, dispatchEventName, calculationOrder });
   },
 
+  /**
+   * A place to fetch data for telemetry after one page is rendered and the
+   * viewer is idle.
+   * @private
+   */
+  async _collectTelemetry(pdfDocument) {
+    const markInfo = await this.pdfDocument.getMarkInfo();
+    if (pdfDocument !== this.pdfDocument) {
+      return; // Document was closed while waiting for mark info.
+    }
+    const tagged = markInfo?.Marked || false;
+    this.externalServices.reportTelemetry({
+      type: "tagged",
+      tagged,
+    });
+  },
+
   /**
    * @private
    */