2020 California Proposition 22

Support
Lyft, Uber, DoorDash, Instacart, and Postmates contributed over $205 million into campaigns supporting Prop 22, making it the most expensive ballot measure in California's history. This included major funding for the Yes on Prop 22 campaign, and promoting the proposed legislation directly to customers when using their app. Beyond in-app messaging, Uber and Lyft also conducted extensive social media and television advertising to persuade voters. Such advertisements informed voters that a "no" outcome for the proposition would put many drivers' occupations in jeopardy, among other messages.

Sponsored support
Some of the companies also forced their workers to support and promote the legislation: Uber sent its drivers in-app messages forcing them to click on either "Yes on Prop 22" or "OK", Instacart ordered its workers to place pro-Prop 22 stickers in customers' shopping bags, and DoorDash forced delivery drivers to use bags saying "Yes on 22".

Title litigation
The ballot title, written by Attorney General Xavier Becerra, is "Exempts App-Based Transportation and Delivery Companies from Providing Employee Benefits to Certain Drivers. Initiative Statute". The Yes on Prop 22 campaign challenged this description as non-neutral in court, but their arguments were rejected by a Sacramento Superior Court judge.

Opposition
The No on Prop 22 campaign was funded by the California Labor Federation, with support from UC Berkeley Labor Center. The campaign received around $19 million in support, mostly from labor groups. Driver groups Rideshare Drivers United, Gig Workers Rising, We Drive Progress, and Mobile Workers United, spoke out against Prop 22. Editorial boards from the New York Times and Los Angeles Times also called on voters to reject Prop 22.

The proposition would add protections specific to app-based workers, different from other independent contractors, but these protections would only apply during the time the worker is "engaged" in fulfilling a specific request and not while the worker is logged in to the app and available to fulfill a request.
Based on the reference text, who were the main parties who supported and opposed Prop 22?
The main parties to support Prop 22 included Lyft, Uber, Doordash, Instacart, and Postmates. The main parties to oppose Prop 22 included California Labor Federation, Rideshare Drivers United, Gig Workers Rising, We Drive Progress, and Mobile Workers United.