tFirstnameMatch checks first names against an index file embedded in the component itself. This component searches first names in the index file according to the input gender and input country you specify in the component settings. When you do not use the gender and country as a search basis, first names are searched throughout all the index, whatever the country is.
The index file has reference first names for about 162 countries. Some of the countries listed in the index have more than 1000 reference first names. Such countries include USA, GBR, AUS, IRL, CAN, FRA, NZL, CHE and NLD. For example, the index file has more than 8000 American first names, more than 4000 British first names, more than 2000 Australian first names and so on.
Some other countries have less than 1000 reference first names stored in the index file. For such countries, it is advisable not to select a country column so that the input first name is checked against all reference first names of all countries in the index file.