For developer

Flow

• Update .pptm
• Save as .ppam

Update .pptm

Update macros

• Alt + F11

Update Custom UI

• Edit customUI/customUI.xml
• Open *.pptm by 7-zip
  • or, you can use an archiver that can open the file as ZIP container.
• Replace customUI/customUI.xml in the .pptm (.zip) file

Save as .ppam

• Open .pptm
• Save as .ppam

NOTE: You cannot edit .ppam file. So don't forget to keep original pptm file!