in general they are a description of what the customizations do as a whole, without explaining how the individual parts contribute to that whole

For example, https://github.com/oracle-samples/netsuite-suitecloud-samples/tree/main/disable-tax-fields describes itself as

This customization uses a script parameter to determine which roles can edit tax fields. If the user is logged in with a role that is not an Administrator or a role that is not specified in the parameter, the script disables the tax fields

it doesnt tell which parts are related to getting that script parameter, parsing it (or even why it requires parsing) and which are related to disablling

it request someone to navigate uncommented code to figure out which piece of code does what

the spoiler here is that i dont believe someone able to do that needs the example

this particular example is extra bad in that it doesnt actually do what it says, so the reader has to figure out how to do the setup themselves to do so

the usual are comments in the code itself to explain each part that needs explaining