I have Facebook Messenger installed on my iPhone. Going into the storage settings of the phone reveals that the app is currently taking up over 2GB, making it the single largest app on my already strapped-for-space phone, which is pretty steep for a messaging app. Delving deeper reveals that the app itself is only 127MB, and the rest is taken up by
Documents & Data, which in iPhone terminology is the data that a given app works with; here it can only mean the actual conversations stored, including any photos and videos.
So, I'm wondering whether it's possible to delete messages from the Messenger app in order to free up some of the space being taken by those conversations, without also having those conversations be removed in the web app? In other words, does deleting messages from Messenger also delete them from the web app?