I'm not necessarily arguing for this, but there are at least three bugs that are open where the issue is that the text that's delivered (typically help text) is inaccurate for a given platform. I'm going to point all of those bugs as blocked by this one.

one option (preferred) is to never deliver text for platform-agnostic applets that is platform-specific.

another option (perhaps) is to a platform-specific strings.txt file where needed. That is, if the text for SOMEAPPLET_FOO for controller in SomeApplet needs to read "press the center button...", and on Fab4 reads "touch the item...", and for all else reads "select the item", there would be these files:

squeezeplay_jive/share/applets/SomeApplet/strings.txt
squeezeplay_fab4/share/applets/SomeApplet/strings.txt
squeezeplay/share/applets/SomeApplet/strings.txt
squeezeplay/share/applets/SomeApplet/SomeAppletApplet.lua
squeezeplay/share/applets/SomeApplet/SomeAppletMeta.lua

the build process would then overwrite the platform-specific strings.txt file in the build, thus delivering platform-specific strings as needed.

Note that this solution would not account for multiple skins within a single platform, e.g. Touch and Remote for Fab4.

I have a strong preference to find a solution that's as simple as possible here, otherwise we're going to end up with a mess on our hands.