Hey, all app data are kept as JSON files. You can edit it easily with a text editor like VS Code or Notepad++. You just need to connect Playdate in data mode. The format of data is not documented, but when you add one item to the app, then it will have an example to follow. For example. Events look like this
{
"createdAt":734261931,
"date": {
"day":8,
"month":4,
"year":2023
},
"id":"AQSJMJPJENPW",
"repeat":1,
"title":"Pocket Planner v3"
}
(with a note that “repeat” is not used/implemented).