A more thorough explanation:

Upon information or belief

A phrase used in legal documents to indicate that a statement or allegation is based on the speaker's knowledge or belief, but not necessarily on direct personal knowledge. This phrase is often used to protect the speaker from being charged with perjury.

• "Upon information or belief, the defendant was seen leaving the scene of the crime."
• "I am informed and believe that the plaintiff has no evidence to support their claim."

In the first example, the speaker is indicating that they did not personally witness the defendant leaving the scene of the crime, but they have received information or have reason to believe that this is true. In the second example, the speaker is stating that they do not have direct evidence to support their claim, but they believe it to be true based on information they have received.