Does anybody know how they synchronize the AC waveform on these plug-in things?
I have been operating on the understanding that you can smash DC sources together but not AC. It sounds like I could parallel inverters with this tech. That would be cool.
Power electronics have become cheap enough that inverters, including ones that synchronize to an existing network, are quite easy to manufacture even for home use. And yes, running multiple such in parallel is possible, and actually supported by some of the "balcony PV"-inverters sold in Germany, not least to sneakily circumvent the 800W regulatory limit. You can even mix balcony PV with multiple home battery units, if you want. Of course one still needs to take care that the cabling won't be overloaded, and especially the battery units are still so expensive that they need to last way longer than their warranty time before you can break even.
"every kilowatt-hour generated by a plug-in solar panel is one less the utility sells to a customer"
No, that would be true only if all balcony panels were battery-buffered in one's home. But buffer batteries for home use are still quite expensive, so depending on how many years they actually last, they may or may not break even against the savings from power you did not have to buy. For most people, balcony PV is less of a profit center, and more of a virtue signal "look, I'm doing my part for non-fossil energy!". The utilities of course hate balcony PV, and while the safety issues are just a pretense, they do have a point that balcony PV provides the grid with even more power exactly at the times when there is already more than enough available from the existing PV farms. It would really help if both centralized and decentralized battery storage became cheap enough that every kWh from PV could easily be stored somewhere.
I wonder if this boils down do anything more than "well yeah you can unlock the boot-loader to install GrapheneOS".
They've had phones with unlockable boot loaders literally the whole time
Yes, but with significant red tape and data harvesting to go through before you received a "code" to free your phone from the boot loader lock-down. So it would be a new thing if all you had to do was pressing a button to confirm you want to "unlock" the phone.
By working faithfully eight hours a day, you may eventually get to be boss and work twelve. -- Robert Frost