src/vs/workbench/services/extensionManagement/browser/webExtensionsScannerService.ts/WebExtensionsScannerService/getCustomBuiltinExtensionsFromCache
class WebExtensionsScannerService:	private async getCustomBuiltinExtensionsFromCache(): Promise<IWebExtension[]> {
		const cachedCustomBuiltinExtensions = await this.readCustomBuiltinExtensionsCache();
		const webExtensionsMap = new Map<string, IWebExtension>();
		for (const webExtension of cachedCustomBuiltinExtensions) {
			const existing = webExtensionsMap.get(webExtension.identifier.id.toLowerCase());
			if (existing) {
				// Incase there are duplicates always take the latest version
				if (semver.gt(existing.version, webExtension.version)) {
					continue;
				}
			}
			/* Update preRelease flag in the cache - https://github.com/microsoft/vscode/issues/142831 */
			if (webExtension.metadata?.isPreReleaseVersion && !webExtension.metadata?.preRelease) {
				webExtension.metadata.preRelease = true;
			}
			webExtensionsMap.set(webExtension.identifier.id.toLowerCase(), webExtension);
		}
		return [...webExtensionsMap.values()];
	}