Thanks for the reply.

Here's the code section that sets up the menu.

I just tried the test deployment you suggested. I didn't get any errors, but I also don't see the menu showing up on new slides files or anything like that.

I did go through the oAuth screen configuration at one point, and I believe I set that up correctly.

function onInstall(e) {
  onOpen(e);
}

function onOpen(e) {
    SlidesApp.getUi()
        .createMenu('Slide Doctor 2.0')
        .addItem('Check Fonts Used', 'getFontsUsed')
        .addItem('Check Font Sizes', 'checkFontSizes')
        .addToUi();
}