src/vs/workbench/services/extensionManagement/electron-sandbox/extensionManagementService.ts/ExtensionManagementService/installVSIXInServer
class ExtensionManagementService:	protected override async installVSIXInServer(vsix: URI, server: IExtensionManagementServer, options: InstallVSIXOptions | undefined): Promise<ILocalExtension> {
		if (vsix.scheme === Schemas.vscodeRemote && server === this.extensionManagementServerService.localExtensionManagementServer) {
			const downloadedLocation = joinPath(this.environmentService.tmpDir, generateUuid());
			await this.downloadService.download(vsix, downloadedLocation);
			vsix = downloadedLocation;
		}
		return super.installVSIXInServer(vsix, server, options);
	}