Question: What is the name of the quadrennial international men's football championship that the 2018-19 UEFA Nations League is a qualifier for?

Context articles: UEFA Euro 2020 qualifying
UEFA Nations League
2018–19 UEFA Nations League A
2018–19 UEFA Nations League B
UEFA Euro 2020
2018–19 UEFA Nations League
2018–19 UEFA Nations League C
UEFA Euro 2016
2018–19 UEFA Nations League D
UEFA Euro 2024

The UEFA Euro 2020 qualifying tournament is an upcoming football competition that will be played from March 2019 to March 2020 to determine the 24 UEFA member men's national teams that will enter into the UEFA Euro 2020 final tournament.
 The competition will be linked with the 2018–19 edition of the UEFA Nations League, giving countries a secondary route to qualify for the final tournament.
 For the first time since 1976, no team will automatically qualify for the UEFA European Championship as the host country.
The UEFA Nations League is an international association football competition, to be contested by the senior men's national teams of the member associations of UEFA, the sport's European governing body.
 The first tournament is due to commence in September 2018, after the 2018 FIFA World Cup, and the winner will be decided in June 2019.
 The competition will largely replace international friendly matches currently played on the FIFA International Match Calendar.
The 2018–19 UEFA Nations League A will be the top division of the 2018–19 edition of the UEFA Nations League, the inaugural season of the international football competition involving the men's national teams of the 55 member associations of UEFA.
 League A will culminate with the Nations League Finals in June 2019 to crown the inaugural champions of the UEFA Nations League.
The 2018–19 UEFA Nations League B will be the second division of the 2018–19 edition of the UEFA Nations League, the inaugural season of the international football competition involving the men's national teams of the 55 member associations of UEFA.
The 2020 UEFA European Football Championship, commonly referred to as UEFA Euro 2020 or simply Euro 2020, will be the 16th edition of the UEFA European Championship, the quadrennial international men's football championship of Europe organized by UEFA.
The 2018–19 UEFA Nations League will be the inaugural season of the UEFA Nations League, a planned international association football competition involving the men's national teams of the 55 member associations of UEFA.
 The competition, which will be held from September to November 2018 (pool stage) and June 2019 (Nations League Finals), will also serve as part of the qualification process for UEFA Euro 2020, awarding berths in the play-offs which will decide four of the twenty-four final tournament slots.
The 2018–19 UEFA Nations League C will be the third division of the 2018–19 edition of the UEFA Nations League, the inaugural season of the international football competition involving the men's national teams of the 55 member associations of UEFA.
The 2016 UEFA European Championship, commonly referred to as UEFA Euro 2016 or simply Euro 2016, was the 15th UEFA European Championship, the quadrennial international men's football championship of Europe organised by UEFA.
 It was held in France from 10 June to 10 July 2016.
 Spain were the two-time defending champions, having won the 2008 and 2012 tournaments, but were eliminated in the round of 16 by Italy.
 Portugal won the tournament for the first time, following a 1–0 victory after extra time over the host team, France, in the final played at the Stade de France.
The 2018–19 UEFA Nations League D will be the fourth and lowest division of the 2018–19 edition of the UEFA Nations League, the inaugural season of the international football competition involving the men's national teams of the 55 member associations of UEFA.
The 2024 UEFA European Football Championship, commonly referred to as UEFA Euro 2024 or simply Euro 2024, will be the 17th edition of the UEFA European Championship, the quadrennial international men's football championship of Europe organized by UEFA.