Czechoslovakia is no longer a country, it is now the Czech Republic and Slovakia. Abhkazia is not a country. Brunei Darussalam is commonly known as simply Brunei.
It's eSwatini now, not Swaziland, Czechoslovakia isn't a Country anymore, it was one, but it isn't anymore, Brunei Darussalam is Brunei (just like United Kingdom of Great Britain and Northern Ireland is just United Kingdom / UK), and Abkahzia is recognized by LESS THAN TEN U.N. Members, and it never was more than that.