如何更改GNOME 3破折号上的“显示应用程序”按钮？

此按钮是通过“显示应用程序”扩展名添加的，不是吗？此扩展依赖于view-grid-symbolic.svg图标，该图标位于/usr/share/icons/gnome/scalable/actionsGnome图标主题的文件夹中。当您直接下载此扩展并研究其内容时，可以获得此信息。

现在，您有2种方法来替换其图标。
1.您可以使用可缩放图标my-cool-icon.svg代替它：

sudo cp -p /usr/share/icons/gnome/scalable/actions/view-grid-symbolic.svg /usr/share/icons/gnome/scalable/actions/view-grid-symbolic.svg.bak
sudo cp my-cool-icon.svg /usr/share/icons/gnome/scalable/actions/view-grid-symbolic.svg
cd /usr/share/icons ; sudo gtk-update-icon-cache gnome

The last string updates the cache of your icons to make your new icon appear. If it won't, restart Gnome.
This method isn't the best one, as it replaces one of the system icons, which may be used by some other application. That's why the second one is preferable.

2. You should find where this extension is located and alter its code, so it will point to another icon. First, create this icon:

sudo cp my-cool-icon.svg /usr/share/icons/gnome/scalable/actions/show-applications-extension-symbolic.svg

You can find your installed extensions in $HOME/.local/share/gnome-shell/extensions/ folder. Find the folder starting with showapplications@ within it, enter it and find extension.js file. Make a backup of it for safety, open it with your favorite editor and find the next string:

let icon = new St.Icon({ icon_name: 'view-grid-symbolic',

用view-grid-symbolic新的引号替换引号内，即show-applications-extension-symbolic.svg。而已。如果更改没有立即出现，请重新启动Gnome。
如果仍然不可见，请按照上述说明更新图标缓存。

参考