Code change:
export const editorBracketHighlightingForeground5 = registerColor('editorBracketHighlight.foreground5', '#00000000', nls.localize('editorBracketHighlightForeground5', 'Foreground color of brackets (5). Requires enabling bracket pair colorization.')); export const editorBracketHighlightingForeground6 = registerColor('editorBracketHighlight.foreground6', '#00000000', nls.localize('editorBracketHighlightForeground6', 'Foreground color of brackets (6). Requires enabling bracket pair colorization.')); <del> export const editorBracketHighlightingUnexpectedBracketForeground = registerColor('editorBracketHighlight.unexpectedBracket.foreground', { dark: new Color(new RGBA(255, 18, 18, 0.8)), light: new Color(new RGBA(255, 18, 18, 0.8)), hcDark: new Color(new RGBA(255, 50, 50, 1)), hcLight: '' }, nls.localize('editorBracketHighlightUnexpectedBracketForeground', 'Foreground color of unexpected brackets.')); </del> <ins> export const editorBracketHighlightingUnexpectedBracketForeground = registerColor('editorBracketHighlight.unexpectedBracket.foreground', { dark: new Color(new RGBA(255, 18, 18, 0.8)), light: new Color(new RGBA(255, 18, 18, 0.8)), hcDark: 'new Color(new RGBA(255, 50, 50, 1))', hcLight: '#B5200D' }, nls.localize('editorBracketHighlightUnexpectedBracketForeground', 'Foreground color of unexpected brackets.')); </ins> export const editorBracketPairGuideBackground1 = registerColor('editorBracketPairGuide.background1', '#00000000', nls.localize('editorBracketPairGuide.background1', 'Background color of inactive bracket pair guides (1). Requires enabling bracket pair guides.')); export const editorBracketPairGuideBackground2 = registerColor('editorBracketPairGuide.background2', '#00000000', nls.localize('editorBracketPairGuide.background2', 'Background color of inactive bracket pair guides (2). Requires enabling bracket pair guides.'));

Related discussion:
text: <!-- Do Not Delete This! bugreporttemplate --<!-- Please read our Rules of Conduct: --<!-- Read our guide about submitting issues: --<!-- Search existing issues to avoid creating duplicates. --<!-- Test using the latest Insiders build to see if your issue has already been fixed: --<!-- Instead of creating your report here, use 'Report Issue' from the 'Help' menu in VS Code to pre-fill useful information. --<!-- Launch with to check. --Does this issue occur when all extensions are disabled?: Yes <!-- If you answered No above, use 'Help: Start Extension Bisect' from Command Palette to try to identify the cause. --<!-- Issues caused by an extension need to be reported directly to the extension publisher. The 'Help Report Issue' dialog can assist with this. --- VS Code Version: 1.92.0 Commit: Date: 2024-07-31T23:26:45.634Z Electron: 30.1.2 ElectronBuildId: Chromium: 124.0.6367.243 20.14.0 V8: 12.4.254.20-electron.0 OS: Linux x64 6.9.3--generic Steps to Reproduce: theme to Light High Contrast a Javascript file final bracket is black, not red as in other themes
I believe this may be the core cause: The value for hcLight here is just an empty string
Thanks for investigating, looks like this color got forgotten when creating the Light HC theme. I took the same color as used in the overview ruler