Stella Holley is a 26-year-old employee of a paperware manufacturer in or around Seattle, Washington. Like most humans, she is drawn into the Transformers' war by coincidence, but unlike most she does not expressly ally herself with or against the Autobots. Instead, she does what she can to help the Mini-Cons establish a home on Earth, away from the Autobot-Decepticon war, despite any dangers put in her path. She is compassionate, brave and proud, and endlessly impressed at how alike humans and Mini-Cons are, despite their physical differences. She can understand the Mini-Cons' standard binary language thanks to a mental link of the sort formed when a Mini-Con bonds with a "Bulk".
She mentions having a cheerleader outfit, though we never see her in it.
(The bikini makes up for it, though)
Micron Legends: Linkage Mini-Comics
Stella first encountered the Transformers as she entered her company's parking garage after work. The Super Stunt Mini-Con Team of Redline, Flat-Out and Servo had just turned her car into a turbo cannon via Powerlinx in order to destroy a pair of pursuing Fixer Bugs. After Redline formed a mental link with her and explained their plight, she hid the Mini-Cons in her home and helped them in their plans to build a Mini-Con haven on Earth.
She accompanied the Team and the newly-awakened Rollbar to the Deccan Plateau in India, where a shuttle from Cybertron had landed. Stella was to act as the interpreter for the Mini-Cons to negotiate for technology from the shuttle, should the shuttle pilot be an Autobot. (In the event it was a Decepticon, they had jury-rigged a portable warp-gate small enough for only their use to escape through.) When the Speed Chaser Mini-Con Team of Unicron-aligned Mini-Cons attacked, Stella managed to defend a mode-locked and upended Servo from a Fixer Bug, but it was the intervention of Scavenger that saved Stella and the Super Stunt Mini-Cons in the end. Stella talked with Scavenger, and he let the Mini-Cons have his ship on the grounds that they forget they ever saw him. However, she began to suffer the effects of heatstroke shortly after, and the Team quickly got her home with their new shuttle.
After the Sonic Assault Mini-Con Team joined up with Redline and crew, Stella went with the Mini-Cons to one of the Hawaiian Islands, where Redline set up a device that would unlock the Master Key program that would give all Mini-Cons unrestricted access to a vast power well, enabling them to break their programming blocks and Powerlinx-activated servility programs. Redline entrusted Stella with the protection of the last two Mini-Con storage panels he kept inside him while he underwent the upgrade process.
When the monstrous Ravenus ensnared Servo and Twirl, Stella fought back to save them in a battle mech made from her car, transformed by Powerlinx energy provided by Flat-Out and Falcia. She was able to knock Servo free from his link-port, but Ravenus escaped with Twirl. Realizing they needed more backup, Stella released the two Mini-Cons Impulsor and Quench from the storage panels, and the two called their team leader, Kingbolt, in to assist.
With Ravenus restored to his original, uncorrupted Autobot state and the Doomstone he held within him contained, all of the "free" Mini-Cons that had awakened when Redline activated the upgrade gathered on the island in order to return to Cybertron with the Autobots so they could protect the planet from Unicron. After a tearful goodbye, Stella returned to her job, taking up drawing as a hobby and a way of remembering her friends. A year after the Mini-Cons left, her red hair spontaneously began to turn platinum blonde--a sign from her friends they had returned, as Stella had made a passing remark to them about wishing she could change her hair color as easily as they upgraded their systems.
She looks totally better as a redhead, but hey.
It is assumed that she and her Mini-con friends reunited shortly thereafter at the new Mini-Con city on Earth that Redline and his friends created.