In Less there are two kinds of comments. The first is the multi-line comment which is going to be copied to the CSS generated by the compiler. The second is the Single-line comment which does not appear in the final CSS file. Below we can see an example of these two comments:
/* This
is
a
multiline
comment */
// This is a single line comment
After compiling the Less file, the final CSS file will have the following result:
/* This
is
a
multiline
comment */
In Minified file generated by the compiler, both types of comments are going to be removed by the compiler in order to have the smallest possible file size.