A human farming colony in the Attican Traverse, Mindoir was raided in 2170 by batarian slavers, who slaughtered most of the colonists. Those not fortunate enough to die immediately were subjected to horrific cranial implants that the batarians used to control them. The Alliance dispatched troops to drive the batarians out, but their defenses were too strong. The Marines were pinned down, forced to watch the suffering colonists but unable to reach them. The atrocity on Mindoir may have been a batarian retaliation against humanity's aggressive colonization of worlds in the Skyllian Verge.
If Commander Shepard has the Colonist background, the Commander was born into a farming family on Mindoir and was sixteen when the raid came. Shepard's friends and relatives were all killed, but Shepard survived and was rescued by an Alliance patrol. Shepard can also meet another survivor of Mindoir, a girl named Talitha suffering from Stockholm Syndrome after marines killed her batarian "masters".
If Shepard has the Spacer background, Shepard's mother and her friend Lieutenant Ernesto Zabaleta served on the carrier SSV Einstein, which responded to the Mindoir raid. The atrocities the slavers inflicted on their victims caused Zabaleta to become afflicted with Post-Traumatic Stress Disorder, which Shepard can later attempt to help treat.
If Shepard has the War Hero background, Officer Eddie Lang mentions that when Shepard was awarded the Star of Terra for acts of heroism on Elysium, he viewed the broadcast of the ceremony on Mindoir, indicating the settlements on Mindoir were rebuilt.
Mass Effect 2
Mindoir has a regular shuttle route to Nos Astra on Illium. Due to security advisories, after attacks on several human colonies, the route is canceled until further notice. If Shepard has the Colonist background, a news broadcast will reveal that Mindoir has won the right to use Shepard's likeness on its colonial seal.
Mass Effect 3
During the mission to investigate a Prothean artifact on Eden Prime, if Shepard has the Colonist background, party banter will comment on how much the people of Eden Prime have gone through, first with a geth attack, and now a Cerberus occupation. They'll continue to say that the people are strong and will rebuild, to which Shepard will retort: "They rebuilt Mindoir. It wasn't the same."