Feels good to see a JS lib last that long and still be actively maintained, deprecating obsolete features and adapting to the new ways we use our browsers without breaking BC (or else explaining how to migrate). Coming from Symfony (PHP), this just feels right: keep moving but make it easy to follow along.
Is this a Symphony thing or are external dependencies significantly more reliable in the PHP ecosystem in general? Last time I wrote PHP was 9 years ago and those times everyone I knew just copy-pasted all the external code they found. I know that package managers are the thing now and I'm using nuget for my .NET projects (and npm, which is a must if you do any front-end dev), however, I feel like I'm having more dependency management issues than the good ol'days in spite of using a language with static type checking.
I'm not saying "vendor everything" but maybe some vendoring helps, especially when every package author seems like they've taken the philosophy of "doing one thing, doing it well and breaking everything on every update".