My Icon shows OS build: 10.0.10586.494 and I know for sure that I had at least 1 OTA Update pushed around mid-July. The "original" UPGRADE from Windows 8.1 Denim was "co-announced" by both Microsoft and Verizon ... but, it was "Upgrade Advisor" that - as I recall - kicked off the whole process. I do have "Windows Insider app" installed, but I just don't remember if I used Insider or just plain "Windows Update"?
However, this must be Microsoft and NOT Verizon as Verizon "discontinued the Icon" almost 2 years ago?
So if you got Win10 in July when it was announced for the Icon, what you got was the original Win10 that came out early this year (or on Insider last fall, if memory serves). This is evidenced by your *.10586.* version. Insiders are on the *.14393.* version right now, and as of today, while I haven't seen any announcements yet for release, today is the day that release will become generally available (GA). What Verizon does with that GA is up to Verizon, and they will likely hold it for a while (if they ever release it, since Icon is discontinued). If you want the goodness that is Anniversary Update without waiting for Verizon, you can switch to Insider, go with fast ring, get the install, and if you don't want to take part in the next wave of updates that will become the next update to Windows 10, you can immediately leave the insider program. A quick search should turn up the recent article on Windows Central telling how to leave insider - but you MUST leave WHILE you are on a release build, or you won't be able to leave, if I remember right. I just skimmed over the article at the time, but that seems to be what I recall.
To answer your question, the update that you received on the 10586 builds came from Verizon through Update Advisor app. Yes, shocking, I know.