An AH Cliché. In OTL Congo became the colony of a relatively small European power, Belgium, and so in AH it is customary for the region to instead become the colony of a comparable country.
Notable examples include Aragon (in Decades of Darkness), Venice, Denmark, Switzerland, and the Netherlands.
Reactions to this cliché by AH.commers
fortyseven once came up with the parodic meta-example of the 'Congolese Congo'.