The whole table
Chains
Everything on a desk connects to everything else, and nearly all of it will physically plug in. That was never the question. The question is what the path gives you once it does, and these are the 6 places it gets decided.
3 of them are stated outright in the listings, if you read the right line. The other 3 are not stated anywhere, and this site says so rather than filling the gap.
| What you plug in | What the listing states | What is not stated | Where it can cap | Read it |
|---|---|---|---|---|
| A monitor over an HDMI cable | A refresh rate, a resolution, and the word HDMI | Which HDMI version the input is, and what the cable is certified for | Not stated At the cable, if the cable is the weakest link in the path | An HDMI cable of an unstated version |
| A screen over USB-C | That there is a USB-C input, and what the panel is | Whether that USB-C port at either end carries a picture | Not stated At the machine port, if it does not support the video alternate mode | A USB-C port that carries power and not video |
| A second monitor alongside the first | What each screen is, on its own | How many external displays the machine drives | Not stated At the machine, on a figure only the manufacturer page carries | One laptop and two screens |
| A keyboard or mouse with no cable and no receiver | Bluetooth, and sometimes that no receiver is included | Whether your machine has a Bluetooth radio | Stated cap At the machine, on a radio the listing never promised | A Bluetooth-only device and a machine without Bluetooth |
| A wireless keyboard and mouse with receivers | That a receiver is included, and often which port it uses | How many USB-A ports your machine has left | Stated cap At the machine, when the ports run out | Every receiver takes a USB-A port |
| A stand or a converter under the machine | That it raises the laptop, and sometimes by how much | That the built-in keyboard rises by the same amount | Stated cap At the hinge, because a laptop is one object | The riser lifts the built-in keyboard too |
To run a specific pairing through this, use Link Check. To count what a keyboard and mouse cost in ports, use Port Budget.