Hi,

As you might have already read in the BIP, this is a proposal to enable sharing part of the UTXO set for " lightweight/SPV client which does not have the full UTXO set at hand.". However the status of the BIP is still "draft", which means that it has not yet reached consensus in the community and is therefore not enabled in bitcoin-core. EDIT : I don't know why the bip's status is still "draft" while the changes have been merged to bitcoin-core.

In the link you provided, it is part of a "version" message, used to initiate a connection. It is enable by default and means that you can provide some part of the UTXO set if someone (which would be a SPV node) requests it.

EDIT2 : More about the services.
Since the version message is used to initiate a connection, a field is reserved to signal which services you provide (or signaling your specific behaviour) :

• The NODE_NETWORK service means you can provide full blocks (basically you are a full not pruned node)
• The NODE_GETUTXO service, see above.
• The NODE_BLOOM service indicates you support Bloom filters. You can know a little more about them here : https://github.com/bitcoinbook/bitcoinbook/blob/f8b883dcd4e3d1b9adf40fed59b7e898fbd9241f/ch08.asciidoc#bloom-filters
• The NODE_WITNESS service, indicates you support Segwit (you can decode segwit-specific messages).
• The NODE_NETWORK_LIMITED indicates that you are a pruned node.

They are also well-documented in the code : https://github.com/bitcoin/bitcoin/blob/3f125151998d9fead198fd44243dd64006b5a56b/src/protocol.h#L246