From Grok on what this means:

This is standard legal language from an appellate court (usually in a criminal case) indicating that the court-appointed lawyer for the person appealing (the "Appellant" ) is trying to get off the case.
Breakdown:

Appellant: The person who lost in the lower court and is now appealing.

Appointed attorney:
A lawyer provided by the court (typically because the appellant can't afford one).

Moved for leave to withdraw: The attorney has formally asked the court for permission to stop representing the appellant. Court-appointed lawyers can't just quit; they need the judge's approval.

Has tendered a brief: The attorney has submitted a written legal document (the "brief" ) to the court.

What this usually means in practice (Anders procedure)

This phrasing almost always signals an Anders brief (from the U.S. Supreme Court case Anders v. California, 1967).

In an Anders situation:
The appointed appellate lawyer has reviewed the case and concluded there are no non-frivolous (reasonable) issues to raise on appeal.

Instead of filing a regular merits brief arguing for reversal, they file a special "no-merit" brief that:

Points out anything in the record that might arguably support an appeal (even if weak).

Explains why those arguments would fail.
They simultaneously ask the court to let them withdraw.

The appellant (you or the client) is usually given time to file their own pro se (self-represented) brief raising any issues they want.

The appellate court then independently reviews the entire record to decide if the appeal is truly frivolous. If it agrees, it will likely let the lawyer withdraw and affirm (uphold) the original judgment. If it finds a potential issue, it may appoint new counsel.

This protects the appellant's right to counsel while allowing the lawyer to avoid filing a meritless appeal (which could be unethical).