How to "allow all" in uMatrix
I see often users asking how to "allow all" in NoScript. So I will address the same question here but for uMatrix.
There are four ways to "allow all" in uMatrix. I will present them in order of gentleness, from the less scary way of allowing all to the most scary way of allowing all.
Create a local allow rule for the all cell:
This way the allow rule applies only in the local scope, nowhere else. Assigning an allow rule to the all cell is a soft "allow all", because no narrower block rules will be overriden as a result, i.e. all the block rules imported from the hosts file will still be enforced.
Note that due to the propagation logic of rules in uMatrix, an allow rule on the all cell propagate to all non-blacklisted cells in the matrix, so that if you reload the page, the allow rule will also propagate to newly seen network requests for which there is no explicit block rule.