Twitch TV project some question about API

Hello,
I’m working on TwitchTV project, and here I’ve some questions.
What diferents betwen
https://wind-bow.glitch.me/twitch-api/channels/freecodecamp
and
https://wind-bow.glitch.me/twitch-api/channels/freecodecamp?callback=?

What does this ?callbac=? mean and what it doing?
When I call API I allwais get such mesh

<p>
{"mature":false,"status":"Some GoLang Today #go #golang #youtube","broadcaster_language":"en","display_name":"FreeCodeCamp","game":"Creative","language":"en","_id":79776140,"name":"freecodecamp","created_at":"2015-01-14T03:36:47Z","updated_at":"2018-04-27T16:02:56Z","partner":false,"logo":"https://static-cdn.jtvnw.net/jtv_user_pictures/freecodecamp-profile_image-d9514f2df0962329-300x300.png","video_banner":"https://static-cdn.jtvnw.net/jtv_user_pictures/freecodecamp-channel_offline_image-b8e133c78cd51cb0-1920x1080.png","profile_banner":"https://static-cdn.jtvnw.net/jtv_user_pictures/freecodecamp-profile_banner-6f5e3445ff474aec-
</p>

How I can get clear list of API
Like this

<p>
**/ typeof  === 'function' && 
({
"mature":false,
"status":"Some GoLang Today #go #golang #youtube",
"broadcaster_language":"en",
"display_name":"FreeCodeCamp",
"game":"Creative",
"language":"en",
"_id":79776140,
"name":"freecodecamp",
"created_at":"2015-01-14T03:36:47Z",
"updated_at":"2018-04-27T16:02:56Z",
"partner":false,

</p>.