I believe a change to the last line of org--file-default-apps introduced in 9.5.3 is a bug. For example, the change prevents shell scripts from being recognized correctly, since the mailcap logic in org-file-apps-gnu is no longer included in org--file-default-apps.

Best wishes,
-Craig Stcr1

org.el 9.5.2

(defun org--file-default-apps ()
"Return the default applications for this operating system."
(pcase system-type
    (`darwin org-file-apps-macos)
    (`windows-nt org-file-apps-windowsnt)
    ('org-file-apps-gnu)))

org.el 9.5.3

(defun org--file-default-apps ()
"Return the default applications for this operating system."
(pcase system-type
    (`darwin org-file-apps-macos)
    (`windows-nt org-file-apps-windowsnt)
    (_ org-file-apps-gnu)))

diff

8701c8700
< ('org-file-apps-gnu)))
---
> (_ org-file-apps-gnu)))