George - I'm not sure about that one, sorry, but I think line out is a line signal (as opposed to a speaker signal) and bypass would mean it's as if it's not there.
True bypass was not used on many pedals for years, it means that even though the effect is basically out of the signal chain, it still goes through some of the electronics in the effect so you're not getting the actual signal, it's being modified to a small extent by the circuitry of the electronic switching, like my Ibanez SD 9 distortion pedal. The usual result is it sucks tone out of your rig, most notably treble. As soon as I can round up a box and the parrts to do it, I'm going to make up a true bypass box for my entire pedalboard, leaving only one pedal (first in the chain) so it will have a buffer. (don't ask me to explain a buffer, I don't completely understand it myself, electronics geeks speak something other than normal English).
True bypass means when the effect is off, it's effectively out of the signal chain entirely, except for the mechanical switch. Wah pedals have always been notorious for "tone sucking", due to their electronic design. The only one I've seen that didn't really kill tone was my old Morley Power Wah (chrome box model) which is now dead, I'd have to completely build a new circuit board to revive it,. Which I'm really tempted to do...
If you can solder I would say find a mod you can do to add a true bypass switch, preferably without making any cosmetic changes. That's why I'm not even considering adding one to my SD 9, I'd have to drill a big ugly hole and put in a separate switch...no thanks, it's a vintage pedal I don't wanna drill anything, same as my amp. I'll make minor electronic changes, mostly easily reversible, but nothing cosmetic that involves extra holes in a vintage amp or effect.
Off topic, but I recently tried out a minor mod on my Fender Champ, very easily reversible, simply de-solder the resistor connected to the bass pot and it adds gain but disables the tone knobs. Works great, ceranked to 10 it now has actual distortion, not just a little dirty like it was, and for the first time ever I can get feedback from it. To get it back stock I just re-solder the resistor back in place, it's still sitting there sticking up in midair not touching anything.
That type of mod I don't mind on vintage equipment, easily soldered back in place, cosmetic changes are out of the question. So if you're not using a 35 year old Cry Baby, and it's not too difficult electronically, look up some mods and try them, add a true bypass switch, you can find mods to tweak the tone of wah pedals too, more or less bass/treble, wider sweep range, etc.
Otherwise build a true bypass box. A one switch box isn't too difficult, I'll have to have one with 3 or 4, one for all but the first effect (Arion SAD 1 analog delay, also vintage) for a buffer, depending on whether I keep the one that's acting flaky rigfht now. The main problem people encounter is a loud pop when switched sometimes, that can usually be cured by adding a capacitor from input to ground.
Good article by RG Keen
Here Complete with non-English electronics jargon.
