[herelink SDK] questions , and help

hello everybody ,
is there the sdk for the herelink avelable (and in witch prog language ) ? i want to develop some custom app for my usecase
is thre any documendation avelable ? could i "send " serial messages from the app and have them appere at the serial ports on the air unit ? witch format is the video streamed ?
lastly what is the capacity of the herelink falsh storage ?

thanks in advance