As the center is charge of developing and producing sophisticated weapons for the Syrian regime, it's quite possible it was in the process of improving the precision of Hezbollah's missiles and that a shipment of such weapons was making its way to the Lebanese organization.
Israel has already made its red lines clear in preparation for the next war. One of these lines is the production of precision-improvement systems and their installment on missiles that are later sent to Hezbollah. The big balls of fire that ascended over the area of strike indicate that the target was weapons, perhaps missiles, which were ready for delivery.
This isn't the first time the Jamariya facility was attacked under similar circumstances. The previous time was four years ago, in 2013. The strike the Syrians are attributing to Israel is the second in four days, which allegedly indicates that Israel is unprepared to give up on another red line as well—an Iranian military entrenchment in Syria.
There are other red lines Israel has made clear to the Russians, and through them to Syria. The important thing is that through the strikes, which are becoming more and more frequent, Israel is conveying a strategic message to Russia, Iran and Syria: There is no chance of reaching a political agreement and a calm in Syria as long as the Iranian military presence in Syria continues and the Iranians are the ones calling the shots.
The message is directed primarily at the Russians, who have differences of opinion with the Iranians too over the Iranian strategic presence in Syria. While Russia needs the Syrian rebels' goodwill to reach a political agreement in the country, the rebels have made it clear that they would not accept an agreement which would keep Syrian President Bashar Assad in power as long as the Iranian strategic presence in Syria continues. The alleged Israeli strikes are aimed at making it clear to Iran and to Russia that Israel too won't allow a calm in Syria as long as the Iranians use Syria as their front base against Israel and as a logistic base for arming Hezbollah.
Israel is making all of this clear through the "war between wars." So far, this low-profile and mostly covert war has allowed Israel to prevent the transfer of large quantities of precision-guided missiles to Hezbollah, as well to convey strategic diplomatic messages to Russia, Iran and Turkey. Israeli security officials believe this war is helping postpone the next war and strengthen the Israeli deterrence.
The Russians, who are interested in maintaining their interests in Syria, understand the messages and are making an effort to avoid a situation in which they and their people in Syria would get caught in a clash between Israel and Iran. Russian President Vladimir Putin is interested in pulling most of his forces out of Syria before the general elections in March 2018, and until then he would like to prevent any fighting in Syria.