src/vs/workbench/contrib/externalUriOpener/common/externalUriOpenerService.ts/ExternalUriOpenerService/openExternal
class ExternalUriOpenerService:	async openExternal(href: string, ctx: { sourceUri: URI, preferredOpenerId?: string }, token: CancellationToken): Promise<boolean> {

		const targetUri = typeof href === 'string' ? URI.parse(href) : href;

		const allOpeners = await this.getOpeners(targetUri, false, ctx, token);
		if (allOpeners.length === 0) {
			return false;
		} else if (allOpeners.length === 1) {
			return allOpeners[0].openExternalUri(targetUri, ctx, token);
		}

		// Otherwise prompt
		return this.showOpenerPrompt(allOpeners, targetUri, ctx, token);
	}