: factor-icons ( -- files )
    "resource:misc/icons" dup exists? [
        [ 
            "." directory-files [ ".png" tail? ] filter
            [ normalize-path ] map
        ] with-directory
    ] [ drop f ] if ;

===

[...]
(O) Method: M\ gtk-ui-backend (with-ui)
(O) Word: set-icons
(O) Word: load-icons
(O) Word: factor-icons
(O) Word: directory-files
(O) Word: directory-entries
(O) Method: M\ unix (directory-entries)
(O) Word: (io-error)
(O) Word: unix-error
(O) Method: M\ object throw
(U) Quotation: [
        63 special-object error-thread set-global
        continuation -> error-continuation set-global
        [ original-error set-global ] [ rethrow ] bi
    ]

Unix system call failed:

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