If syscalls are so similar, for instance, like 'read' and 'readv' or 'pread', 'sendmsg' and 'sendmsgv' or 'fork' and 'vfork'.
Does it still make sense to term or classify them as two distinct syscalls?
I wouldn't call any of them similar, except for 'pread' maybe. Each one has a lot of subtle semantics. Either way, it's syscall.tbl that determines whether they are distinct syscalls, not the author's page
It definitely makes sense to have a section "similar syscalls on this architecture" on the details page.
Yes because they have a different "syscall number".
Doesn't really matter if it has the same name or similar (or identical) function. This website seeks to describe the syscall ABI and that means that each number should get it's own entry.
And there is no identical syscalls in the list, they all have slightly different behavior.
It would be nice to make a banner or warning for deprecated or surpassed syscalls. For example (as mentioned in other comments) you should probably use pipe2 instead of pipe and similar other examples.