You tell me the answer after looking at this annotation layer sample
https://transparentgov.net:3200/googlemaps/default?layer_id=15&layer=Government¢er_lat=33.70754623442314¢er_long=-118.29249434923128¢er_zoom=21&url=https%3A%2F%2Fmaps.lacity.org%2Farcgis%2Frest%2Fservices%2FAnnotation%2Flandbase_annotation%2FMapServer&overlayType=overlayType_image&panto=0
annotation is rectangle shape, with text in it.
Annotation is polygon feature layer, but every polgyon is just a rectangle with text in it as image filling.
https://transparentgov.net/json2tree/esri/server/folder.html?url=https%3A%2F%2Fmaps.lacity.org%2Farcgis%2Frest%2Fservices&org=Los+Angeles+CA+navigateLA&_center_lat=34.03873829713124&_center_long=-118.28231400465035&_center_zoom=16&arcgis_online_token=&select_folder=59&select_layer=15