through which function does client hit the server and how does orbit update osquery on client side, I mean what function is specific to that in orbit and like what is the work of tuf.fleetctl.com in this and what does it do, like does it help in updation or stuff like that and in how much time does client hit the server/poll the server or like server hits the client?

hi! are you asking for specific parts of the code? Orbit does updates using The Update Framework, you can read more about how that works in here https://theupdateframework.io/

I wanted to know about the functions that send requests and receive responses to the hosts and to the update framework and to the hosts as well and where are they in the files of orbit?

it all starts here: http://github.com/fleetdm/fleet/blob/3c9d7fd4bb8d1e6f0a1a3dd1c64a9499024f3c6d/orbit/pkg/update/runner.go#L79-L79

So, the checkInterval inside structure is the time after which it checks for updates?

it checks every 10 seconds

and how to find the exact url of the server where it sends requests responses and the headers?

the server URL is specified here http://github.com/fleetdm/fleet/blob/c069f73f1146f72d8076a67786661bca120494cb/orbit/pkg/update/update.go#L68-L68, in http://github.com/fleetdm/fleet/blob/c069f73f1146f72d8076a67786661bca120494cb/orbit/cmd/orbit/orbit.go#L183-L183

I mean whenever I debug I am debugging orbit source code from cmd/pkg.go, I want to debug it from orbit.go and launch my code for debbuging from there, what arguments should I pass to the debugger is my doubt.

depends on your setup. If you use GoLand as an IDE, it's pretty easy

I am using VS Code

So, orbit doesn't have code of update and request stuff but it does this through tuf framework, right?

correct

Also, any idea how to change osqueryd name to like anything else like for e.g: xyz_daemon? without actually changing to much logic

I believe this is something that has been discussed a few times in #general, I don't recall the outcome of it

So ,it can't be renamed?

it probably can, just like any other daemon, but renaming it is not part of the set of standard configurable things in osquery