Why do I get multiple global IPv6 addresses listed in ifconfig?

The address containing ea9a:8fff:fe6d:6aaa is an automatically configured address based on your Ethernet MAC address. You can recognize them because they contain ...ff:fe... in the middle of the last 64 bits. The rest of the bits is derived from your MAC address. Compare

ea9a:8fff:fe6d:6aaa

with

e8:9a:8f:6d:6a:aa

Because some people are worried that making your MAC address visible on the internet would cause content / website providers to track your behavior by your mac address (and such behavior wouldn't surprise me, although they can more easily track you with cookies, browser-local storage etc etc etc) the privacy extensions were introduced.

The address containing 48c8:f262:ebe8:297b is such an address. That is the address that will be used to connect to websites and other outgoing connections. It will change over time to maintain your privacy and make you harder to track.

Both addresses are available for you to use. Outgoing connections will use the privacy address, unless configured otherwise. You can also still receive incoming connections on the MAC address based IPv6 address. This is all done to give you lots of flexibility. If you want you could add even more addresses.

PS: another tool to see IPv6 addresses is

ip -6 addr

It will show you a bit more detail. You will see the word temporary after the privacy address, which indicates what it is.