diff --git a/services/web/config/settings.defaults.js b/services/web/config/settings.defaults.js
index e30bebfd89..ffd23cea7a 100644
--- a/services/web/config/settings.defaults.js
+++ b/services/web/config/settings.defaults.js
@@ -91,6 +91,10 @@ const defaultTextExtensions = [
   'lhs',
   'mk',
   'xmpdata',
+  'cfg',
+  'rnw',
+  'ltx',
+  'inc',
 ]
 
 const parseTextExtensions = function (extensions) {
diff --git a/services/web/frontend/js/features/source-editor/languages/index.ts b/services/web/frontend/js/features/source-editor/languages/index.ts
index bee9b757c3..dd37dbc507 100644
--- a/services/web/frontend/js/features/source-editor/languages/index.ts
+++ b/services/web/frontend/js/features/source-editor/languages/index.ts
@@ -27,6 +27,7 @@ export const languages = [
       'ldf',
       'xmpdata',
       'Rnw',
+      'rnw',
       'lyx',
       'inc',
       'dtx',
@@ -44,6 +45,7 @@ export const languages = [
       'pygstyle',
       'pygtex',
       'ps_tex',
+      'ltx',
     ],
     load: () => {
       return import('./latex').then(m => m.latex())
diff --git a/services/web/frontend/stories/decorators/scope.tsx b/services/web/frontend/stories/decorators/scope.tsx
index a9439d1b98..33bcadda35 100644
--- a/services/web/frontend/stories/decorators/scope.tsx
+++ b/services/web/frontend/stories/decorators/scope.tsx
@@ -186,6 +186,10 @@ const initialize = () => {
       'lhs',
       'mk',
       'xmpdata',
+      'cfg',
+      'rnw',
+      'ltx',
+      'inc',
     ],
     editableFilenames: ['latexmkrc', '.latexmkrc', 'makefile', 'gnumakefile'],
     validRootDocExtensions: ['tex', 'Rtex', 'ltx', 'Rnw'],
diff --git a/services/web/test/frontend/bootstrap.js b/services/web/test/frontend/bootstrap.js
index be859893cb..e3998e68d1 100644
--- a/services/web/test/frontend/bootstrap.js
+++ b/services/web/test/frontend/bootstrap.js
@@ -64,6 +64,10 @@ window.ExposedSettings = {
     'lhs',
     'mk',
     'xmpdata',
+    'cfg',
+    'rnw',
+    'ltx',
+    'inc',
   ],
   editableFilenames: ['latexmkrc', '.latexmkrc', 'makefile', 'gnumakefile'],
 }
diff --git a/services/web/test/unit/src/Uploads/FileTypeManagerTests.js b/services/web/test/unit/src/Uploads/FileTypeManagerTests.js
index fa8a087da1..16c4304060 100644
--- a/services/web/test/unit/src/Uploads/FileTypeManagerTests.js
+++ b/services/web/test/unit/src/Uploads/FileTypeManagerTests.js
@@ -92,6 +92,10 @@ describe('FileTypeManager', function () {
         '/file.TEX',
         '/file.lhs',
         '/file.xmpdata',
+        '/file.cfg',
+        '/file.Rnw',
+        '/file.ltx',
+        '/file.inc',
         '/makefile',
         '/Makefile',
         '/GNUMakefile',