Reconstructions

PS
*baraḳ-/*barḳ- - lightning (Fronzaroli 1965a: 140, 146, 150; Kogan 2011: 194)
PS
*brḳ - to flash (EDA I 250)
Presumably, denominative from *baraḳ-/*barḳ- ‘lightning’
PS
*brm - to be multicolored (Kogan 2011: 199)
PS
*brr - to be filmy or flickering (eyes); evening, dusk (EDA I 191)
Akk. barāru ‘to be filmy (?)’ and barāri ‘at dusk’ seem parallel to Har. īn birbir bātti “to twinkle, to blink” (īn “eye” + the composite verb with birbir as its lexical element) and īr birbirti “late in the afternoon”, literally “the fluttering of the sun” (EDH 44), which admirably fit the two meanings at once. For the former meaning, cf. also Cha. Eža Enm. Gyt. Muh. Gog. Sod. bərbər barä “to shimmer, to flicker (flame), to burn in a bright and wavy way” (EDG 151). It is hard to say whether we are faced with a chance coincidence (independent descriptive formations?) or with a deeply rooted semantic pattern inherited from PS.
PS
*brr - to be clean, clear (EDA I 192)
PS
*brṣ - to shine, to be bright (CDG 108)
PS
*burāṯ- - juniper (Fronzaroli 1969a, pp. 278, 291, 300)
but cf. problems discussed in Kogan 2012: 242
PS
*bry - to turn (EDA I 219)
PS
*bšl - to be cooked, ready, ripe (Fronzaroli 1971: 626, 636, 642; Kogan 2011: 242)
The transitive meaning ‘to boil, cook’ is mostly reserved for causative formations: Akk. šubšulu, Hbr. biššēl, Syr. baššel, Arb. ˀabsala ‘to boil unripe dates’ (TA 28 84), Gez. ˀabsala, Mhr. həbhōl, Jib. ebšél, Soq. ˀébhel, probably Ugr. bšl (DUL 242).
PS
*bŝr - to bring good tidings (EDA B 280)