Unclear updater error message every time MacVim starts

Steps to reproduce

1. Install MacVim via Macports:

sudo port install macvim

2. Start MacVim

Expected behaviour

No error dialog should be displayed or an explanation of the underlying problem and the steps to solve it should be given.

Version of MacVim

MacVim r183 (Vim (null))

MacVim installation method

MacPorts

Environment

Tahoe 26.5.1
Macbook Pro M3 Max
No terminal - opened via double click in e.g. a .txt file or directly on the application

Logs and stack traces

I could not find anything relating to MacVim in /var/log/* - what is this console log the error message refers to?

Vim and MacVim configuration where issue is reproducable

$ cat .vimrc 
set guifont=Hack:h14
set linespace=2

How was MacVim launched?

• by launching MacVim.app in macOS (by using the Dock, Spotlight, or the open command)
• by running mvim/gvim in the terminal

Issue has been tested with clean configuration

• by running mvim --clean (or gvim, supplied by MacVim distribution). You can also use the File → "New Clean Window" menu item within MacVim.
• by running vim --clean (in terminal, supplied by MacVim distribution)
• by running vim --clean (in terminal, other suppliers, e.g. /usr/bin/vim)

Start by reproducing the updater dialog when launching MacVim.app installed through MacPorts, using the clean configuration noted in the issue. Consult the console log referenced by the dialog and trace the startup updater path; done means the dialog is removed or clearly explains the cause and resolution.