Transparency example for the VS Code Default Dark+ theme with vibrancy patch

default-dark-transparent.jsonc

        "[Default Dark+]": {
            "editor.background": "#1d1d1d60",
            "sideBar.background": "#202020C0",
            "activityBar.background": "#20202080",
            "list.activeSelectionBackground": "#12121250",
            "list.inactiveSelectionBackground": "#C0C0C020",
            "list.focusOutline": "#12121250",
            "list.focusBackground": "#0759cb",
            "list.hoverBackground": "#0759cb",
            "list.hoverForeground": "#ffffff",
            "minimap.background": "#18181860",
            "workbench.background": "#00000000",
            "editorGroupHeader.tabsBackground": "#18181860",
            "tab.activeBackground": "#181818A0",
            "tab.inactiveBackground": "#18181860",
            "panel.background": "#18181890",
            "statusBar.background": "#20202080",
            "statusBarItem.remoteBackground": "#00000000",
            "terminal.background": "#10101070",
            "titleBar.activeBackground": "#252525",
            "titleBar.activeForeground": "#989796",
            "titleBar.border": "#49494960",
            "titleBar.inactiveBackground": "#222222",
            "titleBar.inactiveForeground": "#606060"
        },

Add this under your workbench.colorCustomizations and select the Dark+ (default dark) theme after applying the vibrancy patch.