diff --git a/packages/core/src/shared/filetypes.ts b/packages/core/src/shared/filetypes.ts
index 446cabe0a2a..9e0f9ed689e 100644
--- a/packages/core/src/shared/filetypes.ts
+++ b/packages/core/src/shared/filetypes.ts
@@ -265,6 +265,7 @@ export const codefileExtensions = new Set([
     '.pike',
     '.pir',
     '.pl',
+    '.pl1',
     '.pm',
     '.pmod',
     '.pp',