A more thorough explanation:

The Privy Council is the principal council of the sovereign in Britain. It is composed of cabinet ministers and other individuals appointed by the monarch to serve as privy councillors. The council's functions are mostly ceremonial in nature.

The Judicial Committee of the Privy Council is a tribunal established in 1833. It has jurisdiction to hear certain admiralty and ecclesiastical appeals, as well as certain appeals from the Commonwealth. The committee is made up entirely of laypeople, although ecclesiastics may become members of the court if an appeal is brought under the Church Discipline Act. However, even then, the ecclesiastics must be episcopal privy counselors.

For example, the Judicial Committee of the Privy Council was responsible for hearing the appeal in the case of Miller v Prime Minister in 2019. The case concerned the legality of the Prime Minister's advice to the Queen to prorogue Parliament. The committee's decision was not binding precedent in the UK, but it was influential due to the overlapping composition of members of the Privy Council and the House of Lords in its judicial capacity.

Another example of the Judicial Committee's jurisdiction is its role in hearing appeals from Commonwealth countries. For instance, in 2018, the committee heard an appeal from the Caribbean island of Bermuda in the case of Rodrigues v Attorney General of Bermuda. The case concerned the legality of a law that abolished same-sex marriage in Bermuda.