vSpace Pro LTS is recommended for network without internet

Spreadsheet Service
https://developers.google.com/apps-script/reference/spreadsheet

Gmail Service
https://developers.google.com/apps-script/reference/gmail

Triggers
https://developers.google.com/apps-script/guides/triggers

App Maker – retiring Feb 2020
https://support.google.com/a/answer/9682494

Both Linksys and Amazon Eero offer parental control with their Mesh products.

Linksys’s parental controls is called Linsys Shield, it is powered by Trend Micro. It costs $4.99/month or $49.99/year. Besides being an internet filter, this service also block malicious sites. The internet filter offers categories and a blacklist. I don’t know if there is a whitelist. It has predefined age groups that you can modify. You can easily pause the internet on the connected devices and you can schedule pauses. The only drawback is that it will only work on 14 devices on your network.

Aamazon Eero parental control is called Eero Secure. It costs $2.99/month or $29.99/year. Eero Secure offers the same features and the Linsys Shield. In addition it offers the ability to block inappropriate videos on YouTube. Unlike Linksys, Eero Secure can be used on up to 5 networks, just in case you have multiple homes you only have to pay for one subscription. Eero doesn’t list a limit on how many devices will be filtered on your network.
https://eero.com/technology
https://eero.com/shop

Google Chrome has a very nice tool built in it that lets you inspect the page.

In Chrome right-click the page and select Inspect.
On a Chromebook open Chrome and press CTRL-SHIFT-I (not the numeral one).

Then at the top click Sources.
On the left side of the Inspection you will have a list.
Sometimes it will give you the URL outright.
On an item that doesn’t list a URL hold your mouse over the item. A popup might give you the URL. If not, open that item by clicking the triangle on the left and hold your mouse over one of the sub-items.