I do not see what could mean "a standard sub application" of Cygwin.
Cygwin allows Linuxes / Unixes apps to run on Windows when recompiled using the cygwin emulation DLLs.
So, you can have, multiple apps maintained or not available thru the Cygwin installer that manage dependencies.
I most of the times use it for openssl client.
So I removed Filezilla as I did not need it. I suppose it was installed due to a bug.
I know that I do not answer to your question but I am unable to give you a yes/no answer.
Hope this helps.
PS: what you get when you search for openssl in the installer...