diff --git a/src/libs/utils/algorithm.h b/src/libs/utils/algorithm.h
index 1e821a4bcb0..c337d93bb99 100644
--- a/src/libs/utils/algorithm.h
+++ b/src/libs/utils/algorithm.h
@@ -1272,7 +1272,21 @@ QSet<T> toSet(const QList<T> &list)
 #endif
 }
 
-template <class T>
+template<class T>
+QSet<T> toSet(const QVector<T> &vec)
+{
+#if (QT_VERSION < QT_VERSION_CHECK(5, 14, 0))
+    QSet<T> result;
+    for (const T &p : vec) {
+        result.insert(p);
+    }
+    return result;
+#else
+    return QSet<T>(vec.begin(), vec.end());
+#endif
+}
+
+template<class T>
 QList<T> toList(const QSet<T> &set)
 {
 #if (QT_VERSION < QT_VERSION_CHECK(5, 14, 0))
diff --git a/src/plugins/projectexplorer/project.cpp b/src/plugins/projectexplorer/project.cpp
index 158863d39a2..1afc23a5a4c 100644
--- a/src/plugins/projectexplorer/project.cpp
+++ b/src/plugins/projectexplorer/project.cpp
@@ -120,10 +120,10 @@ ProjectDocument::ProjectDocument(const QString &mimeType, const Utils::FilePath
                                  const ProjectDocument::ProjectCallback &callback) :
     m_callback(callback)
 {
+    QTC_CHECK(callback);
     setFilePath(fileName);
     setMimeType(mimeType);
-    if (m_callback)
-        Core::DocumentManager::addDocument(this);
+    Core::DocumentManager::addDocument(this);
 }
 
 Core::IDocument::ReloadBehavior
@@ -142,8 +142,7 @@ bool ProjectDocument::reload(QString *errorString, Core::IDocument::ReloadFlag f
     Q_UNUSED(flag)
     Q_UNUSED(type)
 
-    if (m_callback)
-        m_callback();
+    m_callback();
     return true;
 }
 
@@ -153,12 +152,6 @@ bool ProjectDocument::reload(QString *errorString, Core::IDocument::ReloadFlag f
 class ProjectPrivate
 {
 public:
-    ProjectPrivate(const QString &mimeType, const Utils::FilePath &fileName,
-                   const ProjectDocument::ProjectCallback &callback)
-    {
-        m_document = std::make_unique<ProjectDocument>(mimeType, fileName, callback);
-    }
-
     ~ProjectPrivate();
 
     Core::Id m_id;
@@ -170,6 +163,7 @@ public:
     bool m_hasMakeInstallEquivalent = false;
     bool m_needsBuildConfigurations = true;
     std::unique_ptr<Core::IDocument> m_document;
+    std::vector<std::unique_ptr<Core::IDocument>> m_extraProjectDocuments;
     std::unique_ptr<ProjectNode> m_rootProjectNode;
     std::unique_ptr<ContainerNode> m_containerNode;
     std::vector<std::unique_ptr<Target>> m_targets;
@@ -195,10 +189,19 @@ ProjectPrivate::~ProjectPrivate()
     std::unique_ptr<ProjectNode> oldNode = std::move(m_rootProjectNode);
 }
 
-Project::Project(const QString &mimeType, const Utils::FilePath &fileName,
-                 const ProjectDocument::ProjectCallback &callback) :
-    d(new ProjectPrivate(mimeType, fileName, callback))
+Project::Project(const QString &mimeType,
+                 const Utils::FilePath &fileName,
+                 const ProjectDocument::ProjectCallback &callback)
+    : d(new ProjectPrivate)
 {
+    d->m_document = std::make_unique<ProjectDocument>(mimeType,
+                                                      fileName,
+                                                      [this, fileName, callback]() {
+                                                          emit projectFileIsDirty(fileName);
+                                                          if (callback)
+                                                              callback();
+                                                      });
+
     d->m_macroExpander.setDisplayName(tr("Project"));
     d->m_macroExpander.registerVariable("Project:Name", tr("Project Name"),
             [this] { return displayName(); });
@@ -339,6 +342,28 @@ void Project::setNeedsInitialExpansion(bool needsExpansion)
     d->m_needsInitialExpansion = needsExpansion;
 }
 
+void Project::setExtraProjectFiles(const QVector<Utils::FilePath> &projectDocumentPaths)
+{
+    QSet<Utils::FilePath> uniqueNewFiles = Utils::toSet(projectDocumentPaths);
+    uniqueNewFiles.remove(projectFilePath()); // Make sure to never add the main project file!
+
+    QSet<Utils::FilePath> existingWatches = Utils::transform<QSet>(d->m_extraProjectDocuments,
+                                                                   &Core::IDocument::filePath);
+
+    QSet<Utils::FilePath> toAdd = uniqueNewFiles.subtract(existingWatches);
+    QSet<Utils::FilePath> toRemove = existingWatches.subtract(uniqueNewFiles);
+
+    Utils::erase(d->m_extraProjectDocuments, [&toRemove](const std::unique_ptr<Core::IDocument> &d) {
+        return toRemove.contains(d->filePath());
+    });
+    for (const Utils::FilePath &p : toAdd) {
+        d->m_extraProjectDocuments.emplace_back(
+            std::make_unique<ProjectDocument>(d->m_document->mimeType(), p, [this, p]() {
+                emit projectFileIsDirty(p);
+            }));
+    }
+}
+
 Target *Project::target(Core::Id id) const
 {
     return Utils::findOrDefault(d->m_targets, Utils::equal(&Target::id, id));
diff --git a/src/plugins/projectexplorer/project.h b/src/plugins/projectexplorer/project.h
index 1af8e6c34fe..45c8409d767 100644
--- a/src/plugins/projectexplorer/project.h
+++ b/src/plugins/projectexplorer/project.h
@@ -250,7 +250,13 @@ public:
     // FIXME: Make this private and the BuildSystem a friend
     ParseGuard guardParsingRun() { return ParseGuard(this); }
 
+    // Set project files that will be watched and trigger the same callback
+    // as the main project file.
+    void setExtraProjectFiles(const QVector<Utils::FilePath> &projectDocumentPaths);
+
 signals:
+    void projectFileIsDirty(const Utils::FilePath &path);
+
     void displayNameChanged();
     void fileListChanged();