A stress-free Slav Defense?

I found fascinating the idea presented in this Chess Improver post, which highlights a little-known and analyzed main line variation (5...a5) for Black.

In general, it's something of a Holy Grail for opening study to find sidelines - especially as early as move 5 - that are easy to learn and give good results, allowing you to avoid lots of complex theory to have to understand and memorize.  Even if such lines aren't technically the best, if they're sound and give you a good, easily playable position heading into the middlegame, then it's still a net plus for your chess study and practice; you can then spend your time and energy on other weaknesses in your game (and there always will be more weaknesses than you can comfortably tackle, at the amateur level).

In this particular case it's clear you still have to understand what's going on in the resulting position, but with relatively simple play it seems that Black can do well.  Perhaps I'll try it out the line myself later on.