Pebble assigned its (remaining) assets to a new company (here Pebble Tech (Assignment for the Benefit of Creditors), LLC) which then acts as a trustee, selling the assets and paying creditors to the extent there are funds to do so. It is s like bankruptcy but under state law (the bankruptcy laws most people are familiar with are federal laws), with the primary difference being that there is no court involvement in the process.
To the extent that you believe you are owed money by Pebble, you can submit a claim to the Trustee; to the extent there is excess money raised by the sale of the remaining assets over and above the existing debt (there is a hierarchy of types of debt that get paid, with secured creditors being the highest and contingent creditors -- for example Pebble owners with working watches within the warranty period -- being the lowest), you may get money. I suspect this is highly unlikely, but you can fill out the form and give it a shot.
The proof of claim form is here: http://www.proofofclaims.com/PebbleTech/documents/92