Added some comments.

extras.py

@@ -1,3 +1,5 @@
+# A script that enables merging SD 1.x based models to SD 2.x based models. Replace the same file of WebUI, which should be located at the modules folder.
+
 from __future__ import annotations
 import math
 import os
@@ -396,6 +398,7 @@ def run_modelmerger(id_task, primary_model_name, secondary_model_name, tertiary_
             # this enables merging an inpainting model (A) with another one (B);
             # where normal model would have 4 channels, for latenst space, inpainting model would
             # have another 4 channels for unmasked picture's latent space, plus one channel for mask, for a total of 9
+            # Note: I will keep the original code as a comment so that you can turn it back on whenever necessary.
             if a.shape != b.shape: #and a.shape[0:1] + a.shape[2:] == b.shape[0:1] + b.shape[2:]:
               theta_0[key] = a # just let it go as it is on size mismatch
                 #if a.shape[1] == 4 and b.shape[1] == 9: