Improve javadoc

Author: jandro996

dd-trace-core/src/main/java/datadog/trace/core/propagation/PropagationTags.java

@@ -3,6 +3,7 @@
 import static datadog.trace.api.ConfigDefaults.DEFAULT_TRACE_X_DATADOG_TAGS_MAX_LENGTH;
 
 import datadog.trace.api.Config;
+import datadog.trace.api.ProductTraceSource;
 import datadog.trace.core.propagation.ptags.PTagsFactory;
 import java.util.HashMap;
 import java.util.Map;
@@ -100,9 +101,27 @@ public interface Factory {
    */
   public abstract void fillTagMap(Map<String, String> tagMap);
 
-  /** Add the appsec propagation tag to the propagation tags. */
+  /**
+   * Updates the propagated trace source propagation tag to include the specified product.
+   *
+   * <p>The product value is parsed and interpreted according to the logic in {@link
+   * ProductTraceSource}. This method ensures that the given product is marked in the propagated
+   * trace source.
+   *
+   * @param product the product identifier to be added to the propagated trace source. Refer to
+   *     {@link ProductTraceSource} for details on how the value is interpreted.
+   */
   public abstract void updatePropagatedTraceSource(int product);
 
+  /**
+   * Retrieves the current propagated trace source propagation tag.
+   *
+   * <p>The returned value is an encoded bitfield that represents the included products. To
+   * understand how this value is parsed and interpreted, refer to {@link ProductTraceSource}.
+   *
+   * @return the propagated trace source as an integer bitfield. See {@link ProductTraceSource} for
+   *     details on its structure and usage.
+   */
   public abstract int getPropagatedTraceSource();
 
   public abstract void updateDebugPropagation(String value);