src/vs/workbench/services/themes/common/colorThemeData.ts/ColorThemeData/setCustomSemanticTokenColors
class ColorThemeData:	public setCustomSemanticTokenColors(semanticTokenColors: ISemanticTokenColorCustomizations | undefined, experimental?: IExperimentalSemanticTokenColorCustomizations) {
		this.customSemanticTokenRules = [];
		this.customSemanticHighlighting = undefined;

		if (experimental) { // apply deprecated settings first
			this.readSemanticTokenRules(experimental);
			const themeSpecificColors = experimental[`[${this.settingsId}]`] as IExperimentalSemanticTokenColorCustomizations;
			if (types.isObject(themeSpecificColors)) {
				this.readSemanticTokenRules(themeSpecificColors);
			}
		}
		if (semanticTokenColors) {
			this.customSemanticHighlighting = semanticTokenColors.enabled;
			if (semanticTokenColors.rules) {
				this.readSemanticTokenRules(semanticTokenColors.rules);
			}
			const themeSpecificColors = semanticTokenColors[`[${this.settingsId}]`] as ISemanticTokenColorCustomizations;
			if (types.isObject(themeSpecificColors)) {
				if (themeSpecificColors.enabled !== undefined) {
					this.customSemanticHighlighting = themeSpecificColors.enabled;
				}
				if (themeSpecificColors.rules) {
					this.readSemanticTokenRules(themeSpecificColors.rules);
				}
			}
		}

		this.tokenColorIndex = undefined;
		this.textMateThemingRules = undefined;
	}