What does [Port 1] mean in a USB capture?

Hi there,

so given the following part of a Wireshark packet, taken from a USB capture on Linux while pluging in a USB drive:

1   0.000000000 host    1.0 USBHUB  64 GET_STATUS Request     [Port 1] 
Frame 1: 64 bytes on wire (512 bits), 64 bytes captured (512 bits) on interface 0 Endpoint: 0x80, Direction: IN

What does "Port 1" mean? Does it indicate the physical port number? Since it does not change, when changing the port, this is unlikely...but what does it mean then?

Thanks!