As recommended by Keith Edmunds in 'The Linux Solution' a wiki is a Good Thing™ for documentation, so here is mine.

The entries here will come as the need arises in no particular order. The following list of links will take you to the details for a particular area.

Tunnels

Servers

Alternate routed address space

Redundancy

Langben

Spot

Maggie

Prefix delegation and subnetting

Routing

A managed switch

Mail configuration

Convert HEIF images to JPG or PNG

Managing and editing Wordpress pages

Enable and disable VLAN2

Gate

How to access RigPi

Kermit

VuPlus