Li Hall (next to St. John's Cathedral

Hello,

Recently I noticed, that there is an extension next to the St. John's cathedral, called Li Hall. When I search older pictures or drawings, that particular building has never been marked or mentioned. The Li Hall's exterior however looks like the one of the main cathedral.

Would anyone knows, when this part of church has been built. I have asked several staff members, but none of them knew .

Thanks a lot and kind regards,  Daniel