Eggbun is file based, so a bookmark is really just a folder with a .eggbun.json file inside. You don't need to manage that manually, just add a new file node and select 'bookmark'.
While you can open a web tab with cmd+t whenever you like a bookmark has a set url. For example you can create a web bookrmark for the webflow designer for your marketing site and call it "Marketing Site". When you do opening that bookmark the home button will return to the url you set.
Because bookmarks in Eggbun are just folders you can create nested bookmarks, or put code files inside.
If you want custom behaviors like javascript and css in your bookmark you can just create a .preload.js file inside any bookmark and the bookmark will run that code whenever you load the bookmark, refresh, or navigate. You can use this to hide ads, or sidebars, or add new functionality and buttons.
Because it's all file based if you add Eggbun bookmarks in a git repo you can sync bookmarks and their preload custom behaviors with your whole team.