Running Merge Conflict
JavaScript (ES6), 102 94 93 90 bytes

console.log('Hello',(a=`
&lt;&lt;&lt;&lt;&lt;&lt;&lt;
Mine
=======
Theirs
&gt;&gt;&gt;&gt;&gt;&gt;&gt;
Conflict`.split`
`)[6]||a[1])


If the conflict has been resolved, then there is no sixth line, so it prints the now first line instead. Edit: Saved 3 bytes thanks to @nderscore.