what does "Khulaa Khat" [open letter] mean?

Re: what does “Khulaa Khat” [open letter] mean?

Yeh hai wo mashoor e zamana ad:

Mujhe lagta hai khulla naama shayad unn khutoot ki taraf ishara hai jo angrez sarkar ki taraf se ghalib ki jaidaad ki qurqi (neelam e aam) ke hawale se aate the ya phir ye telegram jaise kisi system ki taraf ishara hai jo jo kisi ihem khabar ko jald pohunchane ke liye istamal kia jata ho.