Syntax Hightlight doesn't show up in Quicklook Extensions in System Settings

[nkKolja]

After performing a fresh installation of Syntax Highlight via Homebrew, I'm unable to use the application due to the following issues:

The extension does not appear in System Settings > Extensions > QuickLook
Only the following extensions are listed:

Tips
Xcode
Affinity Designer/Photo/Publisher

I have already granted the necessary permissions, but the extension remains unlisted, preventing me from using the application.
Steps to reproduce:

Install Syntax Highlight using Homebrew
Navigate to System Settings > Extensions > QuickLook
Observe that Syntax Highlight is missing from the extensions list

Environment:

Installation method: Homebrew
macOS version: 15.2

The homebrew app is installed and managed via a second user, in order to allow multi-user usage of Homebrew. This might be the reason behind the issue.

Can you help me identify why the extension isn't being registered in System Settings?

[schlappette]

I have read that macOS Sequoia 15.0 disables third-party QuickLook plugins, and developers will need to use a different API.

Will Syntax Highlight (and its equally excellent brother QLMarkdown) be updated to work with macOS 15+?

[sbarex]

Syntax Highlight and QLMarkdown have used the new APIs since their first release.

Try to open first the app and then check if the extension appears on the system settings. Also try to put the app on the trash and then back on the Applications folder.

[nkKolja]

I have deleted the app, the additional files that showed up with AppCleaner, I've also removed it with brew.

Then I re-installed it with brew, and I have the same issue.

I open the app, mac blocks it. I go to System Settings > Privacy & Security to allow it, and open it again.
Then I open System Settings > General > Login Items and Extensions > QuickLook, and Syntax Highlight still doesn't show up.

I would like to add that I have a separate root user where Homebrew is installed, and I control it by running brew as that user with sudo. This never lead to errors with other apps or packages installed with brew, so I doubt it is the case, but I thought I should mention.

[sbarex]

homebrew should not be used with superuser privileges. However I have never used it to install applications. I suggest you try to download the app directly from here, from github (https://github.com/sbarex/SourceCodeSyntaxHighlight/releases/tag/2.1.25)

[nkKolja]

Downloading the app directly fixed the problem.

The standard method for using Homebrew on multiple accounts on a single computer, is by having a separate user install Homebrew, and always calling the brew command via that user.

This could be the reason behind the problem so I will update my original comment to add this information. I don't know if it's a general problem to use this app in a multi-user setting?