TSE—“Tastenschalter mit Elastomerschaltsystem” (pushbutton switch with elastomeric contacts)—is a series of centre-illuminated pushbutton switches from East German brand RFT. TSE is described in TGL 36812 from September 1979. TSE switches were designed to accept a central LED, which could be red, green or yellow.
The operating force is given as 130 cN, which is fairly high, and would suggest that these are not suitable for keyboards. However, they were used in the keyboard of an unidentified Eastern Bloc clone of the Sinclair ZX Spectrum, depicted in Mikrocontroller.net forum topic DDR_LeuchtTaster_und_Schalter.
As with TSS, these switches were available in upright and horizontal versions, the latter having the terminals angled through 90°. Both types have an easily-removable external bracket containing extra pins that function as a jumper and help secure the switch to the PCB.