Hi Elisey,
We're glad you found this forum. I think I can point you at the correct resources to get started.
PPro supports CEP (Common Extensibility Platform) panels, which are basically web pages with two super powers:
1. They can access the local file system, and
2. They can drive PPro's ExtendScript API.
Overview:
General CEP page: https://github.com/Adobe-CEP
A Fancy CEP sample panel that shows off everything possible:
https://github.com/Adobe-CEP/CEP-Resources/tree/master/CEP_11.x/Samples/CEP_HTML_Test_Extension-10.0
I think, Elisey, that this is going to be the most useful place for you to begin; the PProPanel, while unrepentantly ugly, shows everything in PPro's ExtendScript API:
https://github.com/Adobe-CEP/Samples/tree/master/PProPanel
Follow the steps in the PProPanel ReadMe, to set up your dev environment.
Here are a few PPro specific things that I think are specific to what you wan to do:
PPro supports the manipulation of clip markers (associated with a specific piece of media) and sequence markers.
Here's PProPanel playing with clip markers:
https://github.com/Adobe-CEP/Samples/blob/5490c33ac8355ba394c693deb10414553b0a5685/PProPanel/jsx/PPRO/Premiere.jsx#L953
Here's PProPanel playing with sequence markers:
https://github.com/Adobe-CEP/Samples/blob/5490c33ac8355ba394c693deb10414553b0a5685/PProPanel/jsx/PPRO/Premiere.jsx#L301
You can get/set markers to your heart's content, based on whatever you like. Among the first questions you're likely to have:
+ PPro assigns each marker a GUID, so you can tell whether your panel is encountering a 'known' marker, that the user has moved to a different time.
+ No, there's no way to add an extra field to PPro's markers. If you'd like to inject unique identifiers of your own into markers, the best approach available today is putting a GUID into the marker comments.
Here is the publlished API for Premiere Pro:
https://ppro-scripting.docsforadobe.dev/
Panel distribution:
You can distribute your panel, free or paid, through the Adobe Exchange store. This will make your extension available to every Creative Cloud user.
Open your Creative Cloud App and go to Stock and Marketplace > Plugins > All Plugins > Premiere Pro
For users who operate disconnected from Creative Cloud (which definitely happens), you can make a signed compressed .zxp file for distribution, and use ZXPInstaller.com or Anastasiy's Extension Manager to install them.
The info above should get you started. I propose that you set up a dev system, play with the sample panels (particularly PProPanel), and reach out for help as needed.
-Dan