clarify doc - need for amp-ad script (#4142)
clarify doc - need for amp-ad script (#4142)


Gregable/amphtml,adtechnology/amphtml,jlucero-contentad/amphtml,AaronCritchley/amphtml,mlb7687/amphtml,yevheniiminin/amphtml,nexxtv/amphtml,DAC-f1h-dev/amphtml,media-net/amphtml,ampproject/amphtml,luciancrasovan/amphtml,taboola/amphtml,clawr/amphtml,BrightcoveOS/amphtml,laterpay/amphtml,taboola/amphtml,sklobovskaya/amphtml,cvializ/amphtml,Gregable/amphtml,keithwrightbos/amphtml,yandex-pcode/amphtml,sortable/amphtml,taboola/amphtml,JuliusThms/amphtml,shawnbuso/amphtml,media-net/amphtml,rifler/amphtml,dotandads/amphtml,smartadserver/amphtml,interspacejp/amphtml,engtat/amphtml,tlong2/amphtml,cory-work/amphtml,mlb7687/amphtml,arealit/amphtml,comScore/amphtml,avimehta/amphtml,DAC-f1h-dev/amphtml,shawnbuso/amphtml,dvoytenko/amphtml,burtcorp/amphtml,cory-work/amphtml,Mobusi-ads/amphtml,sriramkrish85/amphtml,sharethrough/amphtml,rifler/amphtml,dvoytenko/amphtml,ampproject/amphtml,rlugojr/amphtml,src-code/amphtml,ampproject/amphtml,fullspeed-sp/amphtml,DistroScale/amphtml,rsimha-amp/amphtml,sklobovskaya/amphtml,ecoron/amphtml,jasti/amphtml,arealit/amphtml,DAC-f1h-dev/amphtml,pedjoni8/amphtml,koshka/amphtml,jlucero-contentad/amphtml,DistroScale/amphtml,pietergreyling/amphtml,zhangsu/amphtml,src-code/amphtml,techhtml/amphtml,Adtoma/amphtml,BenDz/amphtml,criteo-forks/amphtml,zhucl/amphtml,sharethrough/amphtml,jpettitt/amphtml,aghassemi/amphtml,DistroScale/amphtml,spotxchange/amphtml,DistroScale/amphtml,Mixpo/amphtml,shawnbuso/amphtml,fullspeed-sp/amphtml,rajkumarsrk/amphtml,adtechnology/amphtml,kamtschatka/amphtml,wjfang/amphtml,DAC-f1h-dev/amphtml,criteo-forks/amphtml,zhucl/amphtml,laterpay/amphtml,clawr/amphtml,mlb7687/amphtml,zhouyx/amphtml,ecoron/amphtml,zhouyx/amphtml,rlugojr/amphtml,jasti/amphtml,sortable/amphtml,kmh287/amphtml,Mixpo/amphtml,rlugojr/amphtml,cory-work/amphtml,pietergreyling/amphtml,keithwrightbos/amphtml,techhtml/amphtml,tdrl/amphtml,chaveznvg/amphtml,bpaduch/amphtml,ecoron/amphtml,vmarteev/amphtml,sriramkrish85/amphtml,jmadler/amphtml,ADITION/amphtml,Gregable/amphtml,prateekbh/amphtml,lannka/amphtml,chaveznvg/amphtml,lzanol/amphtml,src-code/amphtml,alanorozco/amphtml,Mobusi-ads/amphtml,Mixpo/amphtml,kixer-com/amphtml,jlucero-contentad/amphtml,voyagegroup/amphtml,rlugojr/amphtml,ericlindley-g/amphtml,AaronCritchley/amphtml,ecoron/amphtml,ericlindley-g/amphtml,lzanol/amphtml,ericlindley-g/amphtml,rsimha-amp/amphtml,yieldmo/amphtml,jdelhommeau/amphtml,nexxtv/amphtml,mhc-gh/amphtml,ericlindley-g/amphtml,yevheniiminin/amphtml,BenDz/amphtml,danielrozenberg/amphtml,adiant/amphtml,honeybadgerdontcare/amphtml,zhouyx/amphtml,sebastianbenz/amphtml,criteo-forks/amphtml,koshka/amphtml,kixer-com/amphtml,adup-tech/amphtml,Adtoma/amphtml,jpettitt/amphtml,clawr/amphtml,lzanol/amphtml,kixer-com/amphtml,bpaduch/amphtml,burtcorp/amphtml,kmh287/amphtml,dotandads/amphtml,honeybadgerdontcare/amphtml,zhouyx/amphtml,yevheniiminin/amphtml,britice/amphtml,avimehta/amphtml,mhc-gh/amphtml,camelburrito/amphtml,tlong2/amphtml,keithwrightbos/amphtml,erwinmombay/amphtml,zhangsu/amphtml,yieldmo/amphtml,sebastianbenz/amphtml,interspacejp/amphtml,Gregable/amphtml,tdrl/amphtml,jmadler/amphtml,spotxchange/amphtml,erwinmombay/amphtml,ADITION/amphtml,sortable/amphtml,jdelhommeau/amphtml,camelburrito/amphtml,devjsun/amphtml,devjsun/amphtml,amoad-amoe/amphtml,jridgewell/amphtml,vmarteev/amphtml,camelburrito/amphtml,adup-tech/amphtml,fullspeed-sp/amphtml,powdercloud/amphtml,yandex-pcode/amphtml,widespace-os/amphtml,mhc-gh/amphtml,arealit/amphtml,pedjoni8/amphtml,danielrozenberg/amphtml,BenDz/amphtml,interspacejp/amphtml,yieldmo/amphtml,sortable/amphtml,honeybadgerdontcare/amphtml,Mixpo/amphtml,media-net/amphtml,techhtml/amphtml,yandex-pcode/amphtml,wjfang/amphtml,interspacejp/amphtml,mlb7687/amphtml,powdercloud/amphtml,jridgewell/amphtml,burtcorp/amphtml,vmarteev/amphtml,alanorozco/amphtml,donttrustthisbot/amphtml,sortable/amphtml,devjsun/amphtml,sklobovskaya/amphtml,fullspeed-sp/amphtml,honeybadgerdontcare/amphtml,adiant/amphtml,interspacejp/amphtml,engtat/amphtml,adtechnology/amphtml,honeybadgerdontcare/amphtml,alanorozco/amphtml,voyagegroup/amphtml,lannka/amphtml,criteo-forks/amphtml,erwinmombay/amphtml,dvoytenko/amphtml,britice/amphtml,laterpay/amphtml,BrightcoveOS/amphtml,keithwrightbos/amphtml,adtechnology/amphtml,gumgum/amphtml,yieldbot/amphtml,AaronCritchley/amphtml,gumgum/amphtml,yevheniiminin/amphtml,interspacejp/amphtml,ruturajv-media-net/amphtml,donttrustthisbot/amphtml,yevheniiminin/amphtml,rajkumarsrk/amphtml,triplelift/amphtml,lzanol/amphtml,BenDz/amphtml,tlong2/amphtml,BrightcoveOS/amphtml,Gregable/amphtml,DAC-f1h-dev/amphtml,spotxchange/amphtml,devjsun/amphtml,erwinmombay/amphtml,src-code/amphtml,ericlindley-g/amphtml,nexxtv/amphtml,gumgum/amphtml,Lith/amphtml,powdercloud/amphtml,jpettitt/amphtml,rlugojr/amphtml,jlucero-contentad/amphtml,yandex-pcode/amphtml,jasti/amphtml,JuliusThms/amphtml,comScore/amphtml,dotandads/amphtml,yieldbot/amphtml,britice/amphtml,sriramkrish85/amphtml,tdrl/amphtml,burtcorp/amphtml,jmadler/amphtml,Adtoma/amphtml,dvoytenko/amphtml,koshka/amphtml,ADITION/amphtml,rsimha-amp/amphtml,voyagegroup/amphtml,DistroScale/amphtml,lannka/amphtml,aghassemi/amphtml,danielrozenberg/amphtml,cvializ/amphtml,vmarteev/amphtml,kamtschatka/amphtml,mhc-gh/amphtml,widespace-os/amphtml,spotxchange/amphtml,BenDz/amphtml,jpettitt/amphtml,amoad-amoe/amphtml,jridgewell/amphtml,donttrustthisbot/amphtml,DistroScale/amphtml,yieldmo/amphtml,bpaduch/amphtml,adup-tech/amphtml,rajkumarsrk/amphtml,yieldbot/amphtml,rifler/amphtml,mlb7687/amphtml,lzanol/amphtml,ampproject/amphtml,media-net/amphtml,alanorozco/amphtml,smartadserver/amphtml,ecoron/amphtml,bpaduch/amphtml,chaveznvg/amphtml,lannka/amphtml,DAC-f1h-dev/amphtml,yieldmo/amphtml,sebastianbenz/amphtml,Mixpo/amphtml,DarXector/amphtml,nexxtv/amphtml,adiant/amphtml,rlugojr/amphtml,cory-work/amphtml,wjfang/amphtml,jasti/amphtml,JuliusThms/amphtml,yandex-pcode/amphtml,pietergreyling/amphtml,comScore/amphtml,mhc-gh/amphtml,zhucl/amphtml,sklobovskaya/amphtml,kmh287/amphtml,Gregable/amphtml,smartadserver/amphtml,engtat/amphtml,powdercloud/amphtml,cory-work/amphtml,bpaduch/amphtml,luciancrasovan/amphtml,rsimha-amp/amphtml,britice/amphtml,Mixpo/amphtml,BrightcoveOS/amphtml,arealit/amphtml,zhucl/amphtml,koshka/amphtml,widespace-os/amphtml,jpettitt/amphtml,wjfang/amphtml,rajkumarsrk/amphtml,yandex-pcode/amphtml,adup-tech/amphtml,avimehta/amphtml,camelburrito/amphtml,rsimha-amp/amphtml,voyagegroup/amphtml,arealit/amphtml,adiant/amphtml,yieldmo/amphtml,zhangsu/amphtml,avimehta/amphtml,kixer-com/amphtml,zhangsu/amphtml,tlong2/amphtml,devjsun/amphtml,cvializ/amphtml,powdercloud/amphtml,chaveznvg/amphtml,dvoytenko/amphtml,adiant/amphtml,lannka/amphtml,yieldbot/amphtml,rifler/amphtml,ruturajv-media-net/amphtml,adup-tech/amphtml,DarXector/amphtml,cory-work/amphtml,kmh287/amphtml,taboola/amphtml,mhc-gh/amphtml,sortable/amphtml,rsimha-amp/amphtml,smartadserver/amphtml,Adtoma/amphtml,ADITION/amphtml,kamtschatka/amphtml,adiant/amphtml,bpaduch/amphtml,jmadler/amphtml,donttrustthisbot/amphtml,adtechnology/amphtml,engtat/amphtml,sriramkrish85/amphtml,widespace-os/amphtml,yieldmo/amphtml,jridgewell/amphtml,shawnbuso/amphtml,luciancrasovan/amphtml,adiant/amphtml,ericlindley-g/amphtml,powdercloud/amphtml,Lith/amphtml,ruturajv-media-net/amphtml,tdrl/amphtml,keithwrightbos/amphtml,adtechnology/amphtml,vmarteev/amphtml,jmadler/amphtml,rajkumarsrk/amphtml,clawr/amphtml,danielrozenberg/amphtml,prateekbh/amphtml,taboola/amphtml,camelburrito/amphtml,Gregable/amphtml,yevheniiminin/amphtml,comScore/amphtml,pedjoni8/amphtml,yieldbot/amphtml,sharethrough/amphtml,jpettitt/amphtml,media-net/amphtml,prateekbh/amphtml,voyagegroup/amphtml,tlong2/amphtml,alanorozco/amphtml,zhucl/amphtml,burtcorp/amphtml,vmarteev/amphtml,media-net/amphtml,jlucero-contentad/amphtml,powdercloud/amphtml,triplelift/amphtml,JuliusThms/amphtml,DarXector/amphtml,cvializ/amphtml,prateekbh/amphtml,sharethrough/amphtml,kmh287/amphtml,laterpay/amphtml,chaveznvg/amphtml,smartadserver/amphtml,sebastianbenz/amphtml,BrightcoveOS/amphtml,techhtml/amphtml,aghassemi/amphtml,triplelift/amphtml,rajkumarsrk/amphtml,camelburrito/amphtml,rsimha-amp/amphtml,arealit/amphtml,Mobusi-ads/amphtml,nexxtv/amphtml,wjfang/amphtml,pietergreyling/amphtml,prateekbh/amphtml,nexxtv/amphtml,widespace-os/amphtml,jridgewell/amphtml,sharethrough/amphtml,jdelhommeau/amphtml,burtcorp/amphtml,triplelift/amphtml,shawnbuso/amphtml,erwinmombay/amphtml,kmh287/amphtml,koshka/amphtml,sklobovskaya/amphtml,jmadler/amphtml,avimehta/amphtml,ampproject/amphtml,AaronCritchley/amphtml,fullspeed-sp/amphtml,BrightcoveOS/amphtml,tlong2/amphtml,mlb7687/amphtml,ADITION/amphtml,Adtoma/amphtml,devjsun/amphtml,kixer-com/amphtml,alanorozco/amphtml,amoad-amoe/amphtml,jridgewell/amphtml,sharethrough/amphtml,laterpay/amphtml,zhucl/amphtml,donttrustthisbot/amphtml,amoad-amoe/amphtml,shawnbuso/amphtml,BenDz/amphtml,lannka/amphtml,ampproject/amphtml,ampproject/amphtml,luciancrasovan/amphtml,dotandads/amphtml,taboola/amphtml,danielrozenberg/amphtml,mhc-gh/amphtml,techhtml/amphtml,tdrl/amphtml,DarXector/amphtml,honeybadgerdontcare/amphtml,AaronCritchley/amphtml,AaronCritchley/amphtml,criteo-forks/amphtml,aghassemi/amphtml,gumgum/amphtml,cvializ/amphtml,shawnbuso/amphtml,voyagegroup/amphtml,dvoytenko/amphtml,sriramkrish85/amphtml,Lith/amphtml,clawr/amphtml,wjfang/amphtml,clawr/amphtml,kamtschatka/amphtml,bpaduch/amphtml,zhangsu/amphtml,jdelhommeau/amphtml,amoad-amoe/amphtml,sebastianbenz/amphtml,koshka/amphtml,zhucl/amphtml,ampproject/amphtml,kamtschatka/amphtml,jpettitt/amphtml,techhtml/amphtml,rifler/amphtml,gumgum/amphtml,danielrozenberg/amphtml,sriramkrish85/amphtml,jdelhommeau/amphtml,laterpay/amphtml,tdrl/amphtml,ecoron/amphtml,dotandads/amphtml,comScore/amphtml,danielrozenberg/amphtml,ruturajv-media-net/amphtml,wjfang/amphtml,pedjoni8/amphtml,aghassemi/amphtml,amoad-amoe/amphtml,zhangsu/amphtml,criteo-forks/amphtml,pietergreyling/amphtml,taboola/amphtml,dotandads/amphtml,Mobusi-ads/amphtml,sklobovskaya/amphtml,DarXector/amphtml,chaveznvg/amphtml,DarXector/amphtml,cory-work/amphtml,smartadserver/amphtml,JuliusThms/amphtml,rajkumarsrk/amphtml,zhouyx/amphtml,cvializ/amphtml,aghassemi/amphtml,pedjoni8/amphtml,Gregable/amphtml,kixer-com/amphtml,media-net/amphtml,keithwrightbos/amphtml,widespace-os/amphtml,engtat/amphtml,triplelift/amphtml,comScore/amphtml,honeybadgerdontcare/amphtml,zhouyx/amphtml,lannka/amphtml,gumgum/amphtml,alanorozco/amphtml,arealit/amphtml,erwinmombay/amphtml,sklobovskaya/amphtml,mhc-gh/amphtml,Mobusi-ads/amphtml,nexxtv/amphtml,comScore/amphtml,prateekbh/amphtml,spotxchange/amphtml,yieldbot/amphtml,alanorozco/amphtml,Lith/amphtml,sebastianbenz/amphtml,engtat/amphtml,luciancrasovan/amphtml,engtat/amphtml,jlucero-contentad/amphtml,fullspeed-sp/amphtml,keithwrightbos/amphtml,spotxchange/amphtml,pedjoni8/amphtml,pietergreyling/amphtml,jasti/amphtml,Lith/amphtml,Lith/amphtml,donttrustthisbot/amphtml,kamtschatka/amphtml,jridgewell/amphtml,gumgum/amphtml,JuliusThms/amphtml,luciancrasovan/amphtml,camelburrito/amphtml,lzanol/amphtml,jasti/amphtml,adup-tech/amphtml,Mobusi-ads/amphtml,src-code/amphtml,prateekbh/amphtml,vmarteev/amphtml,jdelhommeau/amphtml,luciancrasovan/amphtml,yandex-pcode/amphtml,src-code/amphtml,media-net/amphtml,jpettitt/amphtml,voyagegroup/amphtml,donttrustthisbot/amphtml,triplelift/amphtml,Adtoma/amphtml,kixer-com/amphtml,ruturajv-media-net/amphtml,danielrozenberg/amphtml,ruturajv-media-net/amphtml,clawr/amphtml,zhouyx/amphtml,avimehta/amphtml,rifler/amphtml