I would like to integrate this content as iframe or Onebox:
What needs to be done to achieve that?
AI-generated summary
Integration of Snap! Content
A discussion on integrating Snap! content into a platform. Matze wants to embed a Snap! project using an iframe or Onebox, and asked how to do it. dax replied that adding https://snap.berkeley.edu/ to the allowed iframe site setting would allow embedding the URL, and provided examples of iframe code.
Matze thanked dax and expressed surprise at overlooking the iframe option in settings. dax suggested using the admin panel’s search feature to find the iframe setting, and provided a link to the Mozilla Developer Network’s guide to iframe attributes.
Matze mentioned finding the iframe setting before dax’s response, and pfaffman emphasized the usefulness of the site settings’ search feature.
Add https://snap.berkeley.edu/ in the allowed iframe site setting and then you will be able to embed the URL into an iframe on posts:
<iframe src="https://snap.berkeley.edu/project?user=bh&project=py-fractal"></iframe>
You should also set width and height and other parameters
<iframe src="https://snap.berkeley.edu/project?user=bh&project=py-fractal" width="xxx" height="xxx"></iframe>
How could I just overlook the iframe option in the settings? Thank You 
In your admin panel search for “iframe”.
Here <iframe> HTML inline frame element - HTML | MDN a quick guide to the attributes you can use inside the iframe tag on post
Sorry, i found it before. I asked myself how i could have overlooked.
It’s surprising just how useful the search feature of the site settings is. I almost never interact with system settings any other way. Even though you’d figured out it, it bears repeating for others with similar problems.