in src/data/source.ts [255:261]
async function fetchSources(sources: UrlSource[]): Promise<AllPings> {
if (abortController) abortController.abort();
abortController = new AbortController();
const allData = await Promise.all(sources.map(s => fetchSource(s, abortController!.signal)));
checkAndUpdateEtags(allData);
return await joinData(allData.filter(s => s.data !== undefined) as UrlFetchedSource[]);
}