Coudflare's cache headers

I have set up Cloudflare Caching on a dynamic blog and I used the “Purge By URL” API to purge the cached URL on every new update/delete event. It looks like everything is working fine but I just want to make sure that the pages are cached by analyzing the below sample headers:

age →172

alt-svc →h3-23=":443"; ma=86400

cache-control →private

cf-cache-status →HIT

It would be great if someone can help me understand the below results:

cf-cache-status = HIT means that my URL is cached at Cloudflare’s Edge and the response is serverd from Cloudflare and not from my origin server, right?

Does the “age” header mean that this URL was present in the Cache for 172 seconds, true?

What does the alt-svc stand for?

If “ma” stands for max-age (1 day in this case), I have set up “Cache-Level: Everything” and “Edge TTL” to 1 hour and not 1 day. How come is the “ma” set to 86400?

In some cases, the value of cache-control is set to “cache-control →public, max-age=0”. Why am I getting different values when all the page rules are the same?