▁open ▁protocol ▁based ▁on ▁XML . ▁ ▁The ▁concept ▁is ▁inspired ▁by ▁the ▁A PT ▁pack aging ▁manager , ▁which ▁can ▁work ▁with ▁multiple ▁sources ▁( re pos itories ). ▁When ▁the ▁user ▁wants ▁a ▁package , ▁they ▁can ▁use ▁the ▁client ▁to ▁search ▁for ▁sources ▁where ▁the ▁application ▁is ▁stored . ▁ ▁The ▁name ▁A pto ide ▁is ▁formed ▁from ▁the ▁words ▁" AP T " ▁( the ▁Deb ian ▁package ▁manager ) ▁and ▁" o ide " ▁( the ▁last ▁sy ll able ▁of ▁" Android "). ▁ ▁As ▁of ▁ 2 0 1 7 , ▁the ▁A pto ide ▁platform ▁software ▁had ▁been ▁downloaded ▁about ▁ 6 ▁billion ▁times , ▁was ▁used ▁by ▁about ▁ 2 0 0 ▁million ▁users , ▁and ▁was ▁available ▁in ▁about ▁ 4 0 ▁languages . ▁In ▁the ▁various ▁stores , ▁it ▁is ▁possible ▁to ▁find ▁about ▁ 1 ▁million ▁Android ▁apps . ▁ ▁History ▁ ▁A pto ide ▁started ▁as ▁a ▁proposal ▁of ▁Paulo ▁Tre zent os ▁at ▁the ▁ 2 0 0 9 ▁Ca ixa ▁M ág ica ▁Summer ▁Camp . ▁The ▁proposal ▁was ▁accepted ▁and ▁later ▁became ▁what ▁today ▁is ▁A pto ide . ▁This ▁first ▁stage ▁of ▁development ▁was ▁later ▁developed ▁in ▁the ▁scope ▁of ▁S AP O ▁Summer bits . ▁ ▁The ▁idea ▁behind ▁A pto ide ▁came ▁from ▁different ▁sources . ▁On ▁one ▁hand , ▁the ▁research ▁in ▁Linux ▁install ers ▁in ▁Man co osi ▁European ▁Project , ▁Paulo ▁Tre zent os ▁Ph D ▁project ▁and ▁Portugal ▁Tele com