Hi, it seems that this change broke the resolution of browsers from BROWSERSLIST environment variable. Because you are now conditionally calling browserslist.loadConfig only if configFile exists. But there is a case when someone might not use any config file option but only the env variable. In loadConfig method the first that browserslist library does is to return the value of process.env.BROWSERSLIST if it's defined, otherwise, it proceeds with resolving other types of configurations.

Originally posted by @isemanjski in #16858 (comment)