This picture is home of questionings for ages, where, in my own, the rationals explanations are  included in the following range :

1️⃣ Most probable : Human probe residuals, if inconsistencies on the texture do match an atmospheric entry pattern, then it's surely an artifact sent years back by Humans, during the Cold War or even before. Motives range from Space Race winning to falsification of first contact to obtain an incredible informational advantage over adversaries. Or another explanation : a residual piece from an Earth orbiting satellite that moved its way there.

2️⃣ Less probable : Artifact from an Ancient civilization on Mars : if it did not came from Earth or elsewhere, it means that it's there for a few time only, because it isn't covered by Martian dust, which makes this hypothesis fail (because ruins turn to rust). However, it could have been moved.

3️⃣ Even less probable : Natural artifact : due to the visible shaped geometry and curved straight lines, this doesn't match this hypothesis. Furthermore, we can see that this thing is not covered by Martian dust, thus meaning it have been there only for few years (decades or centuries). 

4️⃣ Unknown : Residual from an Alien probe, nonetheless, anticipation works about real Alien capacities nowhere match this strange thing or even its utility — counter-argument : if they do have the capacities to move through space to Earth or Mars, why would they crash ? What would it serve ? *