what's the use of attrbuteName="x" from="0" to ="300"

Question

<svg width="1000" height="250">
<rect width="150" height="150" fill="orange">
<animate attributeName="x" from="0" to="300"
dur="3s" fill="freeze" repeatCount="2"/>
</rect>
</svg>

Answer 1

It's well explained in this lesson
https://www.sololearn.com/learn/HTML/2213/

Answer 2

attributeName*