It's as centralised as they come. The coin is not mines, creators decide when to issue new coins.

Just read their Wikipedia page

Link

Of the 100 billion created, 20 billion XRP were retained by the creators, who were also the founders of Ripple Labs. The creators gave the remaining 80% of the total to Ripple Labs, with the XRP intended "to incentivize market maker activity to increase XRP liquidity and strengthen the overall health of XRP markets."[113][116] Ripple Labs also had a short-lived 2013 giveaway of under 200 million XRP (0.2% of all XRP) with some of the amount given to charities such as the Computing for Good initiative, which began offering XRP in exchange for time volunteered on research projects.[117] As of March 2015, 67% of Ripple Labs's original 80% was still retained by the company,[113] with Ripple Labs stating that "we will engage in distribution strategies that we expect will result in a stable or strengthening XRP exchange rate against other currencies."[118] In May 2017, to alleviate concerns surrounding XRP supply, Ripple committed to place 55 billion XRP (88% of its XRP holdings) into a cryptographically-secured escrow. The escrow will allow them to use up to 1 billion monthly and return whatever is unused at the end of each month to the back of the escrow queue in the form of an additional month-long contract, starting the process all over.[119][116] The amount of XRP distributed and their movement can be tracked through the Ripple Charts website.[120]