UTF explanation, example, formatting chapter

Author: satoshisstream

blip-0010.md

@@ -22,6 +22,19 @@ This bLIP is licensed under the CC0 license.
 
 The sender of the payments (the Podcast app) needs to input some metadata so the podcast host can identify whom the payment is for. Most fields are optional. 
 
+### Formatting and encoding
+A flat key-value json structure is used where below keys can be set. The string is then encided into `utf8` and attached to the keysend payment. Receivers of messages must be aware there is no guarantee for the order of the keys.
+
+Sample JSON string, containing a selection of keys:
+`{"app_name": "Castamatic", "app_version": "8.0.6", "value_msat_total": 49960, "url": "https://feeds.buzzsprout.com/1844352.rss", "podcast": "Mere Mortals", "action": "stream", "episode": "The Art Of NFT's & Aimless Wandering", "episode_guid": "Buzzsprout-9931017", "value_msat": 97940, "ts": 574, "name": "Podcaster", "sender_name": "Peter"}`
+
+Treated as `utf8` the hex value of this json record would be:
+`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`
+
+If a field is indicated to be a `str` in the fields-list, that means it is a JSON string (within quotes) and `int`s are plain numbers.
+
+### Fields
+
 Identifying the podcast **required**: use any of `podcast`, `feedID` or `url`. **guid preferred**
 * `podcast` (str) Title of the podcast
 * `feedID` (int) ID of podcast in PodcastIndex.org