An egg icon that for years marked profiles of new Twitter users has gone, a victim of “trolls” who often hid behind them to launch anonymous online attacks.
S (An egg) icon
←どんな [that]
for years
S icon
V [marked]
O profiles [of] (new Twitter) users
V [has gone],
たまご型のアイコンはなくなった
補足,
a victim [of] “trolls” 荒らしの犠牲者
←どんな [who]
S (trolls)
V [(often) hid]
補足
[behind] them
補足
V [to launch]
O (anonymous online) attacks.
トロルはアイコンの後ろに隠れてる
（匿名のオンライン）攻撃するために