As of r183 local file & folder saves are now enabled by default in beta releases of Construct. This means in beta releases you don't need to tick 'Enable experimental features' in Settings to use local file & folder saves - but you will still need to do that to use it in future stable releases. This is because the underlying Chrome feature is still itself experimental and subject to change, and so in theory things could break in future, and we don't want to expose stable release users to that potential breakage. However hopefully this makes it easier to use the feature and will get it more testing (although by now we're pretty confident the feature is working well). The original post has been updated, including stopping describing the feature as experimental, although it is still limited in its availability until Chrome fully ships the feature.