Operating systems may apply circles, rounded squares or other masks to installed app icons. A generic square resize does not prove that important artwork remains inside the safe area under every mask.
Purpose any is an honest default
The generated 192 and 512 declarations use purpose any. That tells a supporting browser these are ordinary icons without claiming mask-aware padding. FavBundle does not write any maskable or any-maskable token and does not label the package PWA-certified.
Design the adaptive icon separately
A true maskable workflow needs a visible safe-zone overlay, deliberate padding and previews under several masks. It may require a simplified artwork variant rather than adding whitespace mechanically. Keep that asset separate, test it on intended platforms and then add its own manifest declaration.
Verify in the destination
Place the files at the paths named by the snippet, serve the manifest with an appropriate content type, clear favicon caches, and inspect real browser tabs, bookmarks and install surfaces. Keep the source artwork and compare small edges, contrast and crop. A structurally valid package proves its own bytes and names, not that every browser or operating system will choose the same asset or display it identically.