src/vs/workbench/contrib/extensions/browser/extensionsWorkbenchService.ts/ExtensionsWorkbenchService/resolveQueryText
class ExtensionsWorkbenchService:	private resolveQueryText(text: string): string {
		text = text.replace(/@web/g, `tag:"${WEB_EXTENSION_TAG}"`);

		const extensionRegex = /\bext:([^\s]+)\b/g;
		if (extensionRegex.test(text)) {
			text = text.replace(extensionRegex, (m, ext) => {

				// Get curated keywords
				const lookup = this.productService.extensionKeywords || {};
				const keywords = lookup[ext] || [];

				// Get mode name
				const modeId = this.modeService.getModeIdByFilepathOrFirstLine(URI.file(`.${ext}`));
				const languageName = modeId && this.modeService.getLanguageName(modeId);
				const languageTag = languageName ? ` tag:"${languageName}"` : '';

				// Construct a rich query
				return `tag:"__ext_${ext}" tag:"__ext_.${ext}" ${keywords.map(tag => `tag:"${tag}"`).join(' ')}${languageTag} tag:"${ext}"`;
			});
		}
		return text.substr(0, 350);
	}